Foreword - lehrerseminar-forschung.de · bee-blood as an alkali. ... With bees it is very easy to do so in the laboratory. 15. How far have you gotten in nature study?2 1 Sentence

Foreword

The present book has been published over the last 12 years in numerous small editions. Again and again, out of my teaching experiences and continual striving for a “goethean chemistry,” it has been altered and expanded. Although since the conclusion of the last editions, two years have elapsed, there came (aside from corrections) large-scale changes in the present edition. This includes chapters on buffer-activity and its related physiology. Such a chapter was absent in the earlier editions. Through conversations with Anthroposophically-oriented medical research, out of hunches and searching, we developed definite ideas. In co-working with Reinhard Schoppmann they took shape. The teacher is provided with a well-grounded main lesson block structure. In every last detail they receive a concrete offering. That can lead to being unproductive. Fortunately, so much is offered, that they must choose and select. Thus they have at least something to do. At the moment, unfortunately nothing more than this can be provided. One must shape the topics very precisely, if one wants to be someone who steers around [the topics of] models and molecules, which is unfamiliar. They lurk ready to leap into the thinking of all those trained in chemistry. And initially they must be taken firmly in hand, if he wants to learn, to go a path without them–a path, which will then lead him back away from this book. Eberhard Durrschmidt and Reinherd Schoppmann have worked through the entire book and thereby clarified much of the contents. They have improved the text and many drawings. Thus they have made the experiments more distinct from the main text. At the end, follow “Accessory topics” which one can find expanded individual themes presented in more detail. They are indicated occasionally in the main text. Without cooperative help this book would be hard to publish. I hope also for the further development of further community work.

Table of Contents CHAPTER 1. INTRODUCTION ................................................................................................. 1

1.1 Interpretation of the Curriculum Indications .............................................................. 1 1.2. The Problem of Forming Chemical Concepts ......................................................... 2 1.3. Human / Social Aspects .......................................................................................... 4 1.4. Overview of the Topics ............................................................................................ 5

CHAPTER II. THE SALTS IN THEIR MANIFOLD FORMS-OF-APPEARANCE ................................. 8

II-1 The Form Language of Salts .................................................................................... 8 II-2 Salt Crystals ............................................................................................................. 9

Exp 1 Outer Observations 9 Exp 2 Trans-Illumination and Cleavage Splitting of Crystals 10

II-3 Dissolving / Solutions ............................................................................................. 12 Exp 3 Solution Streamers 12 Ex 4 Dissolving Crystals From Below Over Time 12 Ex 5 Dissolving Crystals From Below With Warmth 13 Detailed Explorations 13 a. Optical density 13 Ex 6 Streaming Waves 14

II-4: Crystallizing ........................................................................................................... 15 Ex 7 Crystal Formation 15 Ex 8 Growing Crystals (Duration: 2-3 Weeks) 16 Ex 9 Salt Efflorescence 17

II-5. Diffusion and Osmosis .......................................................................................... 17 Ex 10 Absorption of Water out of Plant Parts 17 Ex 11 Green Plants 18 Ex 12 Displacement of Salts by Alcohol 18 Ex 13 Physiological Saline (Table-Salt Solution) 18 Ex 14 Osmotic Tubes and SPICULES 20 The Chemical Garden 20

II-6. Halite/Rock-Salt formations, Production, and Use ................................................ 21 II-5. Further Pedagogical Comments ........................................................................... 24

CHAPTER III QUANTITATIVE AND GEOMETRIC THEMES ....................................................... 26

III-1.Temperature Dependence of The Saturation Point .............................................. 26 E15 Solubility at Different Temperatures 26 E16 Rate of Solubility 26

III-2. Symmetry, Types of Crystals, Minerals ................................................................ 32 Summary Of This Chapter: ....................................................................................... 32 Symmetry In Different Worldly Realms ..................................................................... 32

III-2D Grid Pictures: Drawings Of Crystals In Space ................................................... 36

CHAPTER IV. ACID-GAS AND BASE ................................................................................... 39 IV-1 The Effect of Fire .................................................................................................. 39

Ex21 Crystals In The Fire 39

E23 Regeneration Of Blue Vitriol 41 E24 Complete Decomposition Of Copper Vitriol (Basic Experiment) 41

IV-2. Important Acids ................................................................................................... 46 Sulfuric Acid .............................................................................................................. 46

E25 Characteristics Of Sulfuric Acid 47 E26 Determination Reaction 47

B. Saltpeter salts and Nitric acid E27 Dilution Explosion 47 E28 Decomposition Of Nitric Acid 48 E29 Making Gunpowder 49 E30 Decomposition Of Calcium Nitrate 51 E31 Determination Of Nitric Acid 51 E32 Fuming Nitric Acid 51

Hydrochloric Acid ...................................................................................................... 53 E33 Hydrochloric Acid Through Decomposition Of Calcium Chloride 53 E34 Determination Of Hydrochloric Acid 53 E35 Synthesis From Table Salt 54 E36 Hydrochloric Acid Fountain 54 E37 Stomach Acid 55 E38 Displacement Of Acid 55

IV-3. Important Bases .................................................................................................. 56 E39 Melting Table Salt 56 E40 Production Of Caustic Soda (Duration 20 Min) 57 E41 Caustic Soda And Water 57 E42 The Lime Base 58 E43 Test 58 E44 The Copper Base 59 E45 Hydrolysis 59 E46 The Iron Base 59 E47 Base Displacement (J Petering) 59 E48 The Color Play Of Iron Base 60

IV-4. General Characteristics of Acidity And Alkalinity ................................................ 61 A) The pH Scale and Values ..................................................................................... 62

E49 Dilution Series Of An Acid 62 B) Strong and Weak Acids and Buffer activity .......................................................... 64

E49a Sulfuric Acid And Nail, Formic Acid And Magnesium Ribbon 64 E49b Buffering of Eggwhite and Milk 67 E50 Formation In Mineralogical Process 67 E51 Formation In Plant Process 68 E52 Formation In Animal Substance 68 E53a Acid and Base and Their Effect On Each Other 68 E53b Titration Of Various Acid Solutions 69 IV-D Relation of Salts to their Daughter Products 70

CHAPTER V. ACID-GAS AND BASE ..................................................................................... 72

V-1. Salt Preparation from Acid and Base ................................................................... 72 Ex54 Synthetic Table Salt 72

A. Formation Of Salt Slurry ....................................................................................... 73

Ex55 Production of A Salt Slurry 73 Cupric Earth-Base As A Means Of Neutralization ..................................................... 74

Ex 56 Cupric Earth-Base 74 V-2 Table of Naturally Occurring Salts ......................................................................... 75 V-3 The Concept of Acid-stem and Base-stem ............................................................ 76

Ex 57 Determination Of Chloride 76 Ex 58 Volatilization Of Silver Chloride 76 Ex 59 Qualitative Assessment Of Acid-Parts In Taste 76

V-4 Electrolysis ............................................................................................................. 83 Ex 60 Electrolysis of Sodium Sulfate solution 84

V-5 Inner openness of Salts ......................................................................................... 89 Ex 61 INDEPENDENT SATURATION 91 Ex 62 RECIPROCAL SALT PAIR 92 Ex 63 A Second reciprocal salt pair 92

V-6 Questions of Nomenclature ................................................................................... 94 V-7 Driving Chemical Reactions ................................................................................... 96

CHAPTER VI CHEMISTRY OF ANIMAL JUICES ...................................................................... 97

Images

Image 1 – Halite Salt Crystal ........................................................................................ 10

Image 2 – World map of underground salt deposits ..................................................... 24

Image 3 ........................................................................................................................ 27

Image 4 – Salt Solubility as Function of Temperature .................................................. 28

Image 5 ........................................................................................................................ 32

Image 6 ........................................................................................................................ 33

Image 7 ........................................................................................................................ 37

Image 8 ........................................................................................................................ 37

Image 9 – Dehydration of Blue Vitriol ........................................................................... 40

Image 10 – Complete Decomposition of Copper Vitriol ............................................... 41

Image 11 – The Schema with pathways of water loss for blue vitriol ........................... 43

Image 12 ...................................................................................................................... 44

Image 13 ...................................................................................................................... 44

Image 14 ...................................................................................................................... 45

Image 15 – Decomposition of Calcium Nitrate ............................................................. 51

Image 16 ...................................................................................................................... 52

Image 17 ...................................................................................................................... 53

Image 18 – Synthesis from Table Salt ......................................................................... 54

Image 19 – Hydrochloric Acid Fountain ....................................................................... 54

Image 20 – Sequence of Acids .................................................................................... 65

Image 21 – Artificial Table Salt ..................................................................................... 72

Image 22 ...................................................................................................................... 73

Image 24 ...................................................................................................................... 74

Image 25 ...................................................................................................................... 78

Image 26 ...................................................................................................................... 81

Image 27 – Electrolysis of Sodium Sulfate Solution ..................................................... 84

Image 28 – Individual components as in previous figure ............................................. 86

Image 29 ...................................................................................................................... 86

Image 30 ...................................................................................................................... 89

Image 31 ...................................................................................................................... 89

Image 32 ...................................................................................................................... 90

Image 33 ...................................................................................................................... 91

Salts, Acids & Bases Chap. 1. Introduction

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GRADE 10 CHEMISTRY BY MANFRED VON MACKENSEN (1988)

1.1.1 INTERPRETATION OF THE CURRICULUM INDICATIONS In the faculty meeting (“Conferences”) of 6/17/21 of the first Waldorf school, a teacher had answered Dr. Steiner’s question about chemistry by saying: “My main aim above all was to study the difference between acids and bases.” Dr. Steiner then responded:1

1. That is naturally fine, of course. 2. Have the children got a clear idea [mental picture] of the whole significance

of a salt, an acid, a base? 3. These topics must be done first of all. 4. It is frightful to [lecture] about ‘organic’ chemistry. 5. We must overcome that and broaden the concepts 6. We could achieve a great deal by making a thorough study of what belongs

to this year, namely the characteristic qualities of bases, acids and salts. 7. Then speak about alkaline and acidic reactions, and afterwards connect to

the physiological processes so that they acquire an understanding of them. 8. You can take your start from the opposite reactions, perhaps food-sap (royal

jelly?) and bee-blood, since one has there an alkali and an acid, where they reach a peak in the opposite relationships of bee-blood and bee-juice. [??]

9. In this way we have an entry into physiological processes. 10. You need only develop for yourself the concepts of alkaline & acidic, bases

& acids. 11. Then, as I said, since the bee’s blood and food sap of the bee is a

characteristic example of opposite reactions; food-sap reacts as an acid and bee-blood as an alkali.

12. Show them the polar opposites of bee-blood and food-sap which are in the bees’ digestive organs.

13. It is the same in man; only it cannot be so clearly [characteristically] substantiated.

14. With bees it is very easy to do so in the laboratory. 15. How far have you gotten in nature study?2

1 Sentence numbering by Dr. Mackensen 2 Teacher Conferences, 6/17/21 - vol. II, pg. 28, (Steiner Schools Fellowship, 1987)


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Although acids and bases have already been already been taken up in grade 7 from the starting point of fire, they should be treated in a new introduction and certainly in their “whole significance” (sentence 2) up to forming “clear concepts” (s. 2). We shouldn’t stop with a discussion of ‘organic’ chemistry (s. 4). A much better presentation out of examples from the whole of nature would be achieved by not only treating salts, bases and acids, but the higher idea of ‘saltiness,’ ‘alkalinity’ or ‘acidity.’ Certainly not only by lecturing, but by observing also (s. 6). The theme should be a thoroughly studied (“exhausted”), and also “ordered” (s. 6). The first section should be carried to a preliminary physiological-spiritual grasping of the character of acidic and basic reactions. (Since ‘reaction’ certainly does not mean simply to determine the numerical value of the pH with indicator paper!) From these characterizations, an understanding of physiological processes should arise (s. 7). This study of physiological processes follows as a second theme of the block (s. 3 & 7). The determination of the pH-value (or better: the taste of sourness, etc.) may then form a bridge by bee-blood and plant-sap. We have as a goal, then, the relationships, whereby substances [bee blood] cannot be treated in isolation from the bee and the bee hive. Here the overall relations-biology of the bee-hive, and care for the bee larvae, comes into play (s. 8). This study points beyond the bees (s. 9). In summary ("also") initially, we proceed from the acid and base, to acidic and basic (s. 10). After this, we work from the characteristics of the bees – characterizing instead of analyzing and lecturing on the matter (s. 11). Thereby, the foundational point about transformations of substance will be taken up: inwardly, blood; outwardly, food-sap (s. 12). We develop from here the relationships to the human being (s. 13). With the bees, we can and should use it (the honeycomb with brood) and investigate practically, perhaps in terms of pH measurements. Otherwise we would promote a theoretical way of seeing things, rather than from the point of view of natural-history, which is another topic of study (s. 15). More than half the indications deal with organic chemistry; should half the block be devoted to it?

1.2. THE PROBLEM OF FORMING CHEMICAL CONCEPTS With 10th graders (15-16 years old) in a Waldorf school, a decisive step is undertaken towards a scientific systematics. A formalism surfaces for the first time. The student has achieved a point in the development and maturation of their thinking where, in order for them to take the next step, it is necessary for them to make connections with very limited fields of phenomena, using sharply contoured, understandable concepts. The concepts should be worked through further in thought and applied to each other, so that the experimental observations which clearly explain the area we dealt with, can even be used to predict results. The students now experience for the first time, that through the power of


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a thinking which they have developed for themselves, they are able to bring this inner world into correspondence with the initially obscure, dark phenomena of the outer world. The chemical formalism which is at issue here doesn't yet have the conventional scientific form. If we were to introduce concepts of chemical formulas, molecular structure, even a strongly phenomena-based concept of chemical elements in 10th grade, then the greatest difficulties would arise. On the one hand, some teachers want to give the students the most broad and modern general concepts of technical science, so that relieved of a “factual ballast,” they could move in a systemic overview. On the other hand, at just this age of development, the student's knowledge of phenomena is not yet widened and exercised enough, and this phase of life not sufficiently reappraised, so that they would not be fully able to carry such an abstract overview. If this overview is not founded on manifold fundamentals of chemical phenomena, but rather (as is common today) on simplified, trivialized model-concepts (which are mostly mechanistic), then although the students would certainly be well-trained in abstract possibilities of model combinations and in university terminology, they would lose/unlearn how to independently develop general conceptualizations for themselves, first and tangibly out of ideas they had deeply penetrated, and evaluated for themselves. The capacity for evaluation or judgment we want to train in school is, for most 10th graders, still grasping at emptiness; it has not yet matured beyond the foundational physical-chemical perceptions, to go into very general technical scientific concepts like mole, molar mass, atomic bonding. So, thinking in terms of models is unique in that it is easily intelligible since models don’t make possible any sort of new formations of ideas, but they essentially form a barricade that conceals phenomenological ideas. On the basis of these arguments, in the 10th grade, we work only with a kind of preliminary stage to a later scientific systematics. We don't create a formalism for the whole of chemistry, but rather a limited formalism for one part: the salts, acids and bases. Thereby, in connection with the transformation (decomposition) of salt into acid and base, we should not constantly describe the preparation of salt out of these daughter products. It depends much more on drawing together the past events of salts (their genesis) and their future (splitting up), into characteristic concepts of their present quality. These are acid-residue and base-residue (see the chapter "acid-stem"). They are present as a qualitative pair in every salt. Their makeup rules the reactions. Thereby, the chemistry lessons, which in prior years followed the substances not as compounds but as individual substances, steps forward to a first but still qualitative (not material) concept of constituents: however, this includes only the possibility of their appearance. Initially leading [them] into abstract ideas of this kind, accomplishes one of the appropriate goals in thinking for the tenth grade. The initially surfacing, still groping, epistemological discussion (“what is contained there…”) gives a new impulse to individual thinking and their basic world-view. The field of mineral


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chemistry, which is helpful here for a stimulus for perception, among natural phenomena lies relatively open/accessible nowadays, and already has within itself a systematic character (see below). Nevertheless, it offers a wealth of the most interesting natural phenomena, experiments, and technical processes. Also, for the application of abstract thinking, a richness of material is available (symmetry considerations, crystal drawings, etc.) which avoids otherwise applying it to chemical formulae involving a mere combining of letters, and opens up neighboring world realms (mineralogy).

1.3. HUMAN / SOCIAL ASPECTS What does this block mean for the young person's understanding of life? Can they feel their way into their deepest questions with the concepts developed here? In the years just prior, the classes will have made a stronger separation of the sexes. Certainly, during the elementary school years the child's circle of friends sorts itself out according to sexes without difficulty. Nevertheless, they understand one another, learn together, and in learning experience similar interests, joys and difficulties. In the 10th class, through the more formal terms of address3, we consciously speak to the personality which has meanwhile grown more individual. They now confront the individual problem, how human beings of different sexes can develop a relationship in details, and thereupon how they can learn what previously they simply received through collective experience in the whole group. The class is often seized by such loose, preliminary individual relationships. Also, the class community is in a state of flux. So, perhaps one of the "latent questions" lying deep in the young person’s soul is this: ‘How does polarity of the sexes relate to the basic framework and organization of the world – what does polarity mean for me personally?’ In the acid- and base-stems (-residues) of the salts, we can study how polarities which are nonetheless still in equilibrium or harmony, are carried on into the double-nature of the new formation. In contrast, living beings, by virtue of their inner double-nature, constantly create new acids and bases, next to each other. For they close themselves off from outer world forces (like bases) and at the same time bring outwards motion and personal forces to grasp the world (like acids). Non-living nature destroys acid and base, striving towards neutralization. Through this there are always new processes in the world. – All progress stands on the polarity of self-dissolving and preserving forces. A picture of this is also the pollination of plants. Lastly it exists in overall development of culture.

3 In German this is exemplified by the form of address changing explicitly to "Sie" rather than the more intimate "du"


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By following how polarity acts, balances itself, and in balancing brings about something new, and how this colorful variations plays through the chemistry of salts, profound feelings in the adolescent soul will be illuminated with clear thoughts, which allow them to unconsciously experience connections to the world. The goal is to experience oneself more freely in being human. The analogies provided should only serve to indicate to the teacher the size of the task, to arrange experiences and phenomena and bring them to students’ awareness, allow them to perceive—as analogies shared with students, they remain a literary vehicle. Insofar as we bring them into reactions, the movable, moving, escaping acids and the solid, binding, sinking bases, gradually illustrate polarity for us always in changing variations. Only in exploring many variations will the idea become understandable—and only through the idea do we return with new pleasure to specific variations. The student likes to feel that through either industrial/laboratory production or through biological synthesis of acids and bases he has encountered productive forces of nature that work through polarity. He doesn’t collide against dead facts, rather feels his way into how opposites split apart and also heal themselves once again in becoming something new.

1.4. OVERVIEW OF THE TOPICS The sequence of investigation in the course of the block leads from the whole into the part, and again back to the whole of nature. If one proceeds only analytically, then we have three stages:

Stage 1: Unaltered salts: salt crystals, salt solutions, saturation, osmosis Stage 2: Salt series, salt products (salt "fragments"): bases, acids, water of

crystallization Stage 3: Final products of the series (splinter substances): metals, non-metals,

elements, periodic system Between stage 2 and 3, comes the step: oxidation-reduction reactions, i.e., quite a differently constituted transformation than between salts, acid and bases. With these (redox reactions) we have actually forsaken the realm of salts. Therefore this third stage will only be handled at the periphery, for example with the manufacture of sulfuric acid from native sulfur (oxidation), or the transition from copper to black cupric-oxide. Both instances are not so much for an extension of the systematic penetration of the subject, but as a concrete closure of nomenclature. And, for sulfuric acid, to make the industrial production factual; although we can drive most of the acids out of their salts. Problems with manufacture of alkali will be sketched using the soda process. If time is limited, this chapter


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of the syllabus (acid manufacture) can easily be shortened by omitting a study of the soda-process and reactions with caustic-lime. In order not to slip prematurely into the elemental chemistry of grade 11, we have forgone a detailed study of the contrast of acids and bases based on the distinction of metals and non-metals. This would require that we had worked out a concept of elemental substances (elements) and completed a relative overview of the metallic and non-metal elements. This anticipates the central theme of the grade 11 block. Overall, we understand from the curriculum indications that the block should begin with a detailed treatment and mutual illumination of salt-ness, acidity, and alkalinity. These more inorganic themes, will be deepened by mineralogical, geological, geographical and chemical industrial topics, and finally developed further to concepts of connections in the world of Nature, of the order of physiologic processes in the animal kingdom (bees) and finally in the human realm. The block thereby receives an arrangement already appropriate for 10th grade:

1) Salts in relation to light & weight, environment (hardness, form, symmetry), and in

relation to water (taste, temperature-dependence of saturation concentration, warming with solution, elevation of boiling point, depression of freezing point, salt solutions and living beings, osmosis); supplemental topics: salt deposits and resources, saline waters, saline landscapes

2) Salt decomposition by fire; crystal-water, acidic gas, alkaline residue 3) Various acids in individual experiments: sulfuric acid, nitric acid, hydrochloric acid,

sulfurous acids, carbonic acid (latter best known); typical indicator reactions of pure acids.

4) Individual representatives of the following bases: Earthy-bases: metal ash, metal rust: iron rust (hydrated - Fe(OH)3), copper-black (Cu(OH)2) earth-alkali: burnt lime, magnesia (weak bases) potassium and sodium alkali (strong bases)

5) The combining of acid and base to all sorts of salts. The assembly of salts out of un-isolated acid- and base-residue. Examination of the residue (stem) in the salts via colors and characteristic reaction; electrolysis.

6) Salty, acidic and basic in nature: animal kingdom [bees] and in the realm of the human organism.

Salts, Acids & Bases Chap. 2. The salts in their manifold forms of appearance

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GRADE 10 CHEMISTRY – MANFRED VON MACKENSEN (1988) CHAP. II. THE SALTS IN THEIR MANIFOLD FORMS-OF-APPEARANCE

II-1 THE FORM LANGUAGE OF SALTS

We come now to how to actually carry out the block. In an introductory way we could, for example, sketch out how the language of form in Nature is altered by people. In nature, we find the most intricately shaped forms, which cannot easily be described geometrically (pine cone, rock, leaf blade). Geometric laws certainly underlie the arrangement of petals (e.g. in a rose), the branching (mistletoe) or the arrangement of scales (pine cone). But, these laws describe only the basic arrangement of parts, while the overall form (e.g., a whole leaf with its indented edge and ribs) can not be construed geometrically, and also has a constantly variable form. Many forms, like the spruce tree with its vertical trunk, play to some extent with a hardening of geometric form. However, in general, plant forms lack sharp corners, truly planar surfaces, parallel lines, or right angles. In an urban civilization, people surround themselves with flat floor surfaces, rectangular buildings & interior rooms, and furniture, which are mostly rectangular and planar (the furniture of earlier times had more curved forms). With the rather flat hills of the steppes or harbor wall in the coastal landscape, we begin to see another language of form. The technical forms are often merely modular, simply additive repetitive collections of sameness, as for example, in the framing of a multi-story house. Such a world works as a one-sided contrast to the natural environment, rigid, deadening: it leaves our feelings empty. However, it is just through this that people can experience themselves as individuals, and where art and science (knowledge) can take hold inwardly. With this, the flat planar form of the writing desk is repeated a thousandfold in the flat pages of books. [see also Goethe's Faust: the scholarly Wagner vs. the emptiness Faust feels with modern book learning.]

There is one natural kingdom that echoes the language of technical forms. Its constant angles, plane surfaces, and linear edges are a prominent feature; we are dealing here with the realm of natural crystals, above all the salts. [Salt solutions] can crystallize out on their own, bringing them into this condition of crystalline form. The mineral collector speaks of “crystal stages” and thereby places the well-known play of form into the foreground. With this we realize that we have here a miniaturized image of the forms of our civilization, but much richer, for example in the way the minerals inter-grow and ‘socialize’ with each other. Are not the impoverished technical grid forms a pattern for a legalistic-definition rich thinking, also in human corporations?


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So, now the question may arise, ‘where on the earth do we find a domain of phenomena, where crystals occur and grow, even today?’ If we leave aside rock-crystal (quartz) and other mineralized (insoluble) crystals, we then come to the salt condition. Here we could discuss the Zechstein? and middle-triassic [mussel-lime] calcite salt deposits of central Europe and their special localities, also perhaps the saltpeter deserts (see further details below); finally also we could talk about salt efflorescence and crusts of ‘vitriol’ [sulfate salts], alum, and the like. Initially this has less to do with explaining theories of origin, methods of analysis, or the commercial history of these deposits – this happens later in this block – much more to the point we describe vividly how we encounter salts out in nature, in the landscape. Salt deposits are usually found wherever Nature has come to a death., in dry desert wastes, or in such depths as never affected by groundwater. In temperate climates, salt deposits cannot persist at the earth's surface (see S.108 Salt-mountain formation). A very enthusiastic presentation of the history of a dead man preserved in 'vitriol-water' is given by Johann Peter Hebel in "Schatzkastlein".

A very simple introductory thought for this block is ex: people can only obtain sugar, alcohol, etc. (see Gr9 chemistry) through interrupting natural-processes (by cooking, pressing, distillation); but, salts are locally available in high purity already in Nature–in particular in places where no life pulses (Dead Sea); salts are already dead.

II-2 SALT CRYSTALS

Firstly, we compare the outer forms of wood, metal, and salt-crystals; threby we proceed from the objective. One could—more for themselves—put the question: which ‘life’ it is, out of which rock crystal or the metals have fallen out, at least a very ancient one.

Exp 1 Outer Observations

a) Allow the students to touch objects on a table covered by a cloth, so that the form, roughness, the weight in relation to size (density), and the sensation of warmth, can be found in calm reflective mood and expressed clearly. Example objects could be: snail shell, pine-cone, quartz crystal, rock-salt (halite) crystal, sandstone, rough iron or copper (possibly brass or bronze). Natural items are preferred, which are somehow products of life, which we can chance upon in the foliage of plants or in the soil of earth. In contrast, the metals stand in contrast. (Later, we could ask the further question: out of which ‘life’ is the quartz crystal produced?).


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b) Now, lift off the cloth, allowing a stimulating arrangement of these and other objects to be visible. The quartz crystal is accompanied by a whole variety of salt crystals (from the table, below). Students test one after the other, students test the color (transparency), cleavage colors, form and taste of individual pieces. Through tearing on the one hand, and cleavage on the other, we can investigate the various harnesses (against abrasion and rubbing).

Exp 2 Trans-Illumination and Cleavage Splitting of Crystals

Transparent crystals [large quartz piece!], viewed in suitably diffuse light of the overcast sky, will create the impression of an ‘empty brightness.’ [we see the walls, but the interior is more or less invisible]. If we simulate a thin sun beam streaming into deep shadow, with a small flashlight, then we can completely reverse the above impression: we see a crystal ‘filled with light.’ [the whole substance of the crystal stands out against the dark backdrop]. If we rotate a hexagonal quartz prism in the light beam, we also see light spots dancing about the walls of the room, making a triangular star pattern – the crystal forms the surroundings. The inner order is expressed by a blow on a large halite crystal (table salt): all cleavage pieces are similar.

On the day after these demonstrations, we can put out the question: which differences in forms are expressed between of living beings, and the forms of crystals? Crystals have no specific size as do plant forms. Rock salt cubes occur from 10–4mm up to 1 meter in size. One can turn a crystal (ex: octahedron, or to a lesser degree quartz rock-crystal), without the view in relation to the surrounding being much altered or made unnatural. If we pulverize a larger crystal, often the fragments will occur in the very same form (ex: with table salt, small,

microscopic cubes). this is very different with a crumbled fern-tip. The living forms, with their non-regularity or at least with their orientation to the vertical dimension, have a specialized form with a individually typical size. Confronted by interchange with the environment, they are limited to a definite size. In contrast, salt crystals go out completely into the environment, their faces hint to the infinite.

Halite salt crystal


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Behind such investigations stands primarily the simple striving or organize and classify objects in the world, initially outwardly and then according to their inner character. With the students, we can process and digest the individual characteristics of wood up to quartz into a surveyable table. In hardness and specific gravity, salt crystals lie in the middle position. They form members of a kind of spectrum of salts in the following groups:

Groups of Salt Types Lithified salts (no taste)

Barite, Fluorite, Apatite Semi-Lithified salts (only faint taste)

Gypsum, Calcite, Selenite, Limestone, Dolomite Encrusting Salts (soapy & bitter)

Thenardite (Glauber's salt), Arcanite Aromatic/spicy Salts balanced char., salty taste, aromatic

Table salt, Halite, Sylvite, Ammonium alum Desert Salts

Potash, Soda ash, “Trona” , Chile Saltpeter, Saltpeter, mason's saltpetre Argentite (phot. salts), Cerargyrite

Bitter Salts

Epsom salts, Biscovite, ice melter, (Calcium chloride) Corrosive Salts –astringent, metallic

Kalinite, Alum, Chalcanthite (blue vitriol) iron stone, green vitriol, Aluminum chloride

Among the salts, table-salt stands in the middle. to the one pole, the taste diminishes, solubility disappears (lithification) and the symmetry of the crystal forms is held back, the crystal-habit can tend towards columnar, leafy-plates, or spears. Towards the other pole, the taste becomes very distinctive and one-sided, intense, irritating, leads off in an opposing direction out of the realm of taste. Also, the relation to the surrounding expressed in solubility steps beyond, these slats lose their ability to maintain themselves: their crystals are quickly destroyed by mere air: the vitriols weather and fall apart, the bitter salts melt away. Also, the symmetry again decreases; points or tabular forms arise (naturally always with exceptions).


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The students are initially impressed with the variety of salts. Towards the end of the block this variety can be tied in with a few acid- or base- stems (alkalai, or alkalai-earths). We can now work further simultaneously in two directions. the form-language leads to the crystal forms, specifically to the raster-forms which are further described in chapter 3. the taste leads into solutions and crystallization of salts.

II-3 DISSOLVING / SOLUTIONS Exp 3 Solution Streamers

A thumbnail-size piece of table salt (halite) and perhaps a small quartz crystal next to it, are suspended on thread or thin wires (copper screen or tea sieve) in the upper third of a water-filled flask ,which is as large as possible (5 liter). We could also use crystals of other salts: alum –dissolves only in acidified water, and with copper sulfate – the salty taste of the solution is hardly perceptible. Students around the container and discern faintly visible wave forms and streamers moving down below the undisturbed, hanging salt crystal. After a while, the sharp edges of the crystal become rounded and the surfaces pitted; it appears “sucked off” and resembles more and more the flowing streaks. With table-salt (halite) we can taste the solution, but there is little taste at the surface. The rigid structural language disappears in water and softer forms emerge both in the water and in the crystal. In drawing the submerged waves, one sketches the crystal with sharp lines and angles using a hard pointed pencil; in contrast, for the fluid waves, one uses broad, watery brushstrokes. When the crystal is overpowered by water, it completely loses its structure. How does this occur? Do particles filter down and spread throughout in the water? Does the water change accordingly? Is the salt permanently lost? Dissolution must be a form of magic, because there is no other way for a salt crystal to disappear into nothing (when crushed, we get powder). We prepare further investigations.

Ex 4 Dissolving Crystals From Below Over Time

Place a large (colored) crystal into a high (2L) beaker and observe over the next days how

the solution zone spreads out, but only through the lower zones of the solution in the beaker.


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Ex 5 Dissolving Crystals From Below With Warmth

Fill a 2-liter beaker 2/3 full with look-warm water that has been boiled recently for a few minutes. In a slow stream, pour in 90-100 ml coarse table salt. The experiment works the best if the salt is free of dust; otherwise too much air is carried along. The water in the top of the beaker hardly tastes salty. At the bottom of the beaker, we soon observe a ‘gel-layer’ in which the salt lies. Rapidly heat the beaker (2 burners, with the beaker on 2 wire gauze pads). Soon we see small bubbles slipping out of the salt and rising upward. The boiling-motion should stay restricted to the bottom half of the beaker (reduce to 1 burner); it creates many formations and an upward moving boundary layer. The surface of the water in the beaker remains unchanged: look-warm and sweet, as in the beginning.

Detailed Explorations a. Optical density Remove beaker from heat and place alternately in front of a window and in front of a

cardboard with vertical stripes (with ca. 1 cm width). The stripes appear concentrated by the water relative to the air; and further concentrated at the boundary to the salt solution in the middle of the beaker (in beakers that are too small, this causes scattering due to decreased focal length of the cylinder lens). The boundary to the saturated salt solution, when viewed from below, can cause a mirror effect (total reflection).

b. First depth samples With a 100 ml pipette, remove solution samples from near the surface and from the

lower half of the beaker. For each sample, fill a test tube 2/3 full (both exactly the same height) and use to demonstrate differences in taste and temperature. 1. The concentrated solution is not much oilier (viscous) than the water 2. When placed in a beaker with ample water, the test tube with concentrated solution sinks lower

c. Second depth sample Allow a (not too) fresh egg to sink into the beaker; it floats on the boundary layer. d. Inner layers Using a focused light source for viewing, move the beaker to slightly agitate the layers:

the water surface calms quickly, the lower boundaries swing (sloshes) back and forth as clearly visible layers for quite a while even though the surface layer appears undisturbed.

e. Finally, we can investigate the stickiness of the precipitate from the concentrated solution by rubbing some between the fingers and drying it out.


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Ex 6 Streaming Waves A wire mesh tea-ball or filter paper pouch is filled with a very small potassium permanganate crystal, then hung submerged in a tall glass cylinder (10 liter): solution streamers move downwards. If we tape thin paper on the back side and illuminate the cylinder from the rear, then people can enjoy the weaving, flowing play of colors. On the basis of the experimental observations, students can get the impression of optical and mechanical density (heaviness). A salt solution poured into pure water always streams down to the bottom; with that, it shows some characteristics of the downward-sinking salt crystals.

Just as the phenomena of salts on earth are divided in a two-fold occurrence–in solid and liquid, namely in solid mountain rock layers, and in the world's oceans, so salts also generally seem to have a dual character: crystallized and dissolved. How do these two forms relate to one another? If a crystal dissolves, something is retained and intensified: the crystal was previously inwardly 'empty', open, and homogenous (isotropic) like water. When a salt crystal forms, then the heaviness that is in water is now concentrated [in the solid crystal] while the fluid becomes lighter. Increasing heaviness (density) in a solution always leads to crystallization. In contrast to water, solutions of crystals are somewhat heavier. In the same way, optical density is concentrated and increased [in crystal solutions]. Heaviness and emptiness are comparable in the solid and in the dissolved form, just as the magnitude:

Crystals–as we have already observed–have no typical size, which belongs to their growth. Their form does not depend on the size. Just as with solutions, they can occur in large and small portions. A certain similarity also lies with symmetry. Parallel corners and the corresponding parallel faces contribute to the fact that crystals always lie in the same orientation and [even] appear the same when we flip them around; we call this symmetry. Ideally, this would arise in a weightless, rounded drop.

In total contrast, we experience the formation; here solution and crystal are totally different. Something unexpectedly rigid, edgy, separates itself from the supple fluid. On the other hand, a solution can show itself in manifold motions, it can flow, evaporate or trickle away, also saltwater can form waves at the surface—the crystal is solid. The regular edges and faces point towards the infinite, beyond the earthly plane. So this [crystal] growth is foreign


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to all living growth in the world, foreign also to water, that orients itself in between heaven and earth.

A crystal grows upwards just as well as downwards. Crystals do not assume a particular position in the polarity of lightness and heaviness of nature, nor with respect to each other; they grow through and on top of each other. With crystal growth, a constant form-element comes ever more to manifestation. The shape thereby remains primarily regular. No metamorphosis takes place. Only solution slides over the crystal. If a person sculpts a crystal in clay, they can’t truly emulate this [process of] emergence.

Now it is time to turn ourselves to experiments with crystallization.’

II-4: Crystallizing We can experience the crystallization of salts up close, especially in individual student investigations.

Ex 7 Crystal Formation

Student Experiment: Prepare 400g saltpeter (KNO3) cooked in 0.5 L water and maintained at tepid-warmth (70ºC), until it is dispensed into [warmed] small beakers (100 mL high-form) or test tubes (25 mm diam) for each team of two students. We can even allow students to carefully taste a small drop of solution (spit it out afterwards!) and wait patiently for crystallization to begin. After about 5 minutes, saltpeter ‘needles’ (spicules) begin to form in all directions, from below and from the surface; if we used 460g of saltpeter, it goes even faster. A dirty beaker produces a rapid haziness instead of slowly produced needles. Crystals slowly sink and float to the bottom. As the solution approaches room temperature, crystallization stops. A further careful tasting (and spitting out) of the solution demonstrates that in no way has all the saltpeter been crystallized. b. Overnight larger crystal aggregates form: if one lets a heat-saturated solution of

saltpeter crystallize overnight in a 3 L beaker wrapped with Styrofoam, a wool cloth, or an old coat, then pours off the excess liquid, and places it briefly in a bucket of hot water, one can slide out a garden of crystal needles for display.

c. With recovery of the salt by evaporation on a heater, an efflorescence crawls up out of the container (for ease of salt removal, use plastic container).


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d. An interesting variation is subsequent coloring of the salt solution: in front of the students, one adds a cooling solution of 20g copper nitrate (CuNO3 • 3H2O) rapidly dissolved by heating: The crystals produced do not take on color???

e. One can do the experiment in a similar way with KCl. With this one can observe lovely (interference) colors that appear on the thin crystal sheets when they first form.

Ex 8 Growing Crystals (Duration: 2-3 Weeks)

As an extension of the previous experiment, we can direct the students to grow larger

crystals from salt solutions in a corner of the classroom that is sheltered, with constant temperature and away from the window. Alum, chrome alum, and copper sulfate (Blue vitriol) have good growth characteristics. Copper chloride produces thorny, extremely attractive crystal clusters, but can also produce lumpy and ugly clumps. For growing their own crystals, each student should bring:

ü Two medium-sized jam jars (250 mL) with their name on it ü Short stick (popsicle or skewer) ü Thread (Rayon, Silk or nylon) ü An oblong pebble ü A second glass for decanting ü Scissors

To begin, the thread is weighted down by the pebble and suspended in the saturated solution by the short stick that lies across the mouth of the jar (it also works without the pebble). If crystals form along the thread, or around the pebble, they need to be removed to leave only one, eventually cutting off the pebble and suspending the crystal midway in the jar. On a daily basis, one must remove the ‘parasitic’ crystals from the seed crystal, thread, and jar walls. In alum mostly grow octahedral crystals with small blunt cubic corners. The edges of the octahedron sometimes end in rhombic dodecahedral surfaces. The crystals of chromalum decompose in the air during drying (whitish areas). One can protect them from this if one hangs the fully developed crystal into a saturated aluminum-alum solution. The copper sulfate crystals decompose over longer time periods. One can store them in a sealed jam jar, which has cotton in the bottom with a drop of water (for further advice growing crystals, see appendix)


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Ex 9 Salt Efflorescence (An extension of E7e) over a large platter, containing pieces of wood, charcoal, sand and earth, one pours here and there various saturated salt solutions (blue vitriol, saltpeter, chrome alum, K4Fe(CN)6); place it on the radiator to warm. The next day, we can admire the greatest variety of efflorescence and crusts. In following the evaporating water, salts can sometimes form airy, tree-like shapes; they trace the movement of the ascending water. In order to crystallize salt out of solution, one must make a ‘solidifying’ intervention, for instance cooling (eg moving toward freezing) or evaporation (moving towards drying, hardening). With heating, the solid strives downward, the unburdened water wells forth and we see the flowing streamers rise upwards. With evaporation, the solid follows the path of steam vapor, and builds itself upward into the air, making fine, porous, rising shapes. All this however, always requires outer forces like warmth, air movement etc. On its own, salt never arises from the solution [a supersaturated solution can exist for a while!]. On the contrary: salt tends towards melting. In the steamy, misty atmosphere of enclosed spaces, in leaky cellars, it is always the spot that contains salt that is the first to become wet. This attraction of moisture becomes especially apparent in osmosis, when salt borders on living, sap-permeated things.

II-5. DIFFUSION AND OSMOSIS Ex 10 Absorption of Water out of Plant Parts

a. Salt in Fruit With a knife, bore out enough of a hole in an apple, potato, radish, or the like, so that there is a finger-sized cavity. Fill this hole with dry table salt or slightly moist salt paste, set the object upright in a glass dish. After about an hour, we notice that the salt is now completely moist and fluid seeps out of the hole: taste of concentrated salt with a hint of the type of fruit used (only 1% fruit juice). The next day, several cm of the fruit surrounding the salt-hole has become soft and limp. The limp regions have not only lost their liquid, they have also acquired a strong salty taste that weakens in the still turgid parts (hand out pieces to taste!). This entire movement of substances eventually affects the whole solid fruit. b. Fruit in saltwater Place an unblemished apple or potato in a salt solution and another one into water; the weight of both remains unaffected over the next 24 hours. On the other hand, if one cuts


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the fruit, they lose approximately 1% of their weight after around an hour (weigh dry before and after).

Ex 11 Green Plants Place half of a complete plant with roots in a beaker with 4% table salt solution (“ocean water”). Within at least an hour, the plant is completely limp and appears totally wilted. A plant that has remained exposed to the air for twice the time undergoes the same changes, but one in water does not. To regenerate, we can place the plant in water for a few hours or overnight. The air-dried plant nevertheless remains limp. With the salt-damaged plant it is briefly possible to restore turgor in the leaves. However, the leaves wilt again soon after, even if placed in water. This occurs because the plant tissue has not only lost water to the salt solution [by osmosis & diffusion], it has also absorbed salt. If one analyzes the leaves for salt content (chloride analysis with AgNO3), it is definitely higher than in a water-maintained control plant. The salt solution in the leaves was osmotically active during regeneration and thereby briefly restored turgor to the plant parts, without this being a metabolic process (it becomes and remains apparently dead).—Further experiments and explanations in Appendix under “Osmosis” (pg111).

Ex 12 Displacement of Salts by Alcohol Add a generous shot of alcohol to a saturated table salt or copper sulfate solution. Immediately thick, fine clouds of white or light blue salt precipitates form.

Ex 13 Physiological Saline (Table-Salt Solution) One allows the students to taste a physiological table salt solution (0.8% NaCl) to which the blood corresponding .03% CaCl2 (anhydrous) has been added; ocean water concentration (3% table salt and 0.6% MgCl2- anhydrous) and as a third, water similar in taste to the Dead Sea (11% table salt, 20% MgCl2—anhydrous). The latter experiment shows again the tendency of salts to spread out. In nature the distribution of salts is affected by the outer forces of the atmosphere, surface water currents carry salts into the ocean. Salts can also distribute undisturbed, without this external motion, as long as there is sufficient moisture. One sets up a tall cylinder with water as in Ex 4, and in the bottom a slightly soluble salt, maintained undisturbed and free from temperature and/or light fluctuations (this would be found deep inside the earth, in the dark), to avoid any type of current (convection) in the fluid; nevertheless over the course of


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months the salt concentration distributes itself equally throughout the water. If one were to float a water impermeable disc above the bottom of the cylinder, the disc would remain firmly in its place even though the salt concentration would move upward from the bottom. One could call the motion of the salt a crawling one, a disturbance in the undisturbed. This phenomenon, expressed in a quantitative model, is called diffusion. Diffusion does not only occur in free flowing liquids, it is especially important in gels, in moist meat and fruity bodies.

In our Ex 10a, we observed a particular distortion of diffusion. The exiting solution only has a low percentage of radish juice. What flows out of the apple is mainly water, not juice. When we fill the hole with salt, the salt bordering the hole becomes moist and there forms a thin layer of saturated salt solution. This then continues to pull moisture out of the radish. At the same time, some of the salt diffuses into the radish, in opposition to the aforementioned diffusion current. Of these three processes, namely the movement of water, of fruit-juice, and of salt (solution), the dominant one is the diffusion of water. It can be understood as a type of one-sided water absorption through salt. Such a one-sided diffusion is called osmosis. It is in our case only approximately demonstrated, since also small amounts of the radish’s substances exit with the water, and small amounts of salt enter. A barrier that is impermeable to water in the air, but after immersion allows diffusion of water into a salt solution, but not the reverse diffusion of salt into the diluted or salt free liquid, is designated as semi-permeable. Such a layer is well approximated in cellophane or in the carefully prepared outer skin of a pig’s bladder; but nowhere perfectly.

All in all, solid salt on earth reveals itself as unstable when it somehow reaches the realm of motion from its eternal rest in the hills, either through the life of the atmosphere (precipitation) or nearing parts of living things: It dissolves, swims away and distributes itself in the oceans over the entire earth. The lack of an inner cohesion, which we called “emptiness” above in reference to clear crystals, emerges in a great dissolving-dynamic as a generalization for salts on the earth.

The phenomenon of salt dissolving, to forcefully go into solution and distribute itself, can even produce great pressure. Think of the conventional osmosis experiment with a tube. In somewhat more fanciful form the same is shown in the “chemical garden” (actually a crazy name) with a pressure that repeatedly creates small disruptions:


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Ex 14 Osmotic Tubes and Spicules (or worms and needles)

The Chemical Garden Pre-experiment. One pours not too dilute copper salt solution into a half-concentrated Na (or K) silicate (or vice versa): jellylike clumps. Instead of various salts in sodium silicate one can also add yellow K4Fe(CN)6 to copper sulfate solution. 400 ml concentrated (oily) sodium silicate (‘water glass’) diluted in a 1 L beaker with the same amount of water. Sprinkle over the solution coarse crystalline earth alkaline salts, which sink. The following “grow” especially well in half-concentrated sodium silicate: • Copper nitrate (turquoise blue, partly columnar, twisted forms) • Copper chloride (blue-green, more columnar forms) • Iron III chloride (rust-brown, clumping knots) • Nickel chloride (bright green, sharp towers but also knotty forms thinner than iron

chloride) • Manganese chloride (pale pink threads or delicate, curving shapes) • Magnesium and calcium chloride (white, very delicate, threadlike, root-like forms The sporadic “growth” of the chemical forms is easily observable. Already after 15 minutes there arises a unique, seemingly half mineral, half animal-like (corals, water lilies) underwater landscape, that slowly continues to “grow”.— Concentrated hydrochloric acid is best for quickly cleaning the glassware. Longer exposure to sodium silicate leaves etched spots.

The chemical spicules grow by reaction between the sodium silicate and the introduced heavy metal salts, by forming a skin-like hydroxide precipitate mixed with silica gel. Through this semi-permeable layer, water diffuses towards the inside, bursts the layer, the salt solution runs out, penetrates the sodium silicate and is renewed as the layer. Because the salt concentration is the highest in the bottom of the tube (on the crystal: saturated), the membrane is thinnest at the tip and bursts on top—there results “growth” upwards. Even if this osmosis lets itself be presented as a seemingly growth-like structural process, it leads basically to an excess build-up of pressure, overflow, or disruption. This is especially apparent in germination experiments (see Appendix).


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If an animal or plant is exposed to a sufficiently concentrated salt solution, it will sooner or later shrivel or die through water loss. Organisms with impermeable skin (leather, wax layers) as for instance an apple or an animal beyond the developmental stage of amphibian, manage to stand up to this. We summarize: Salts and salt solutions are not permanent in nature when in contact with moisture. There, they either ‘dissolve’ themselves in (diffusion), or they dry it out osmotically, whereby they dilute themselves and flow away. In general the impression is created that salts and their solutions represent something in the environment that is extraordinarily opened up, practically expansive. This stands badly in contrast to living things, which must always maintain certain isolation. No life can exist in concentrated salt solution. There, nothing can isolate itself.

Salt deposits are locations of wasteland on the earth. No plants enliven the picture; no rainstorms bring about change. Where the crystalline salt persists, there arises a wintery scene. A glittery but rigid expanse. A silent world surrounds the observer, in which no changes occur; it is totally still, natural processes have come to an end. Even the winds, which bring the loose sand dunes of the desert into motion, have no effect on a salt crust.

One could describe a few salt waters found in nature, the ocean, the Dead Sea, Lake Natron (northern border of Tanzania), or the Kara Bugas (a salt lake on the Caspian sea). (Some characteristic descriptions and literary recommendations are in the Appendix).

II-6 HALITE/ROCK-SALT FORMATIONS, PRODUCTION, AND USE

The plant world only needs very weakly concentrated salt solutions.1 The salt requirement in the animal world, especially with herbivores, is higher. For human beings, the daily recommendation for salt is 8 to 16 g. In the typical mixed diet this corresponds to a daily supplement of 4 to 8 g, so around 1 teaspoon = 5g. (In Stuttgart at the end of the eighties, a freight train of cooking salt was consumed yearly, that was ca 1000 tons for 1 million inhabitants). Added to this is the salt requirement for cooking water and the scatterings against nature; further for soap making and in large part for the chemical industry (chlorine-alkali-electrolysis). Nevertheless, taxes were only raised for edible salt (formerly 12 pennies / kg in the BRD, ended in 1993).

1 They don’t taste salty, and can only be termed salty on the basis of their analyzed trace salt content. Such a questionable terminology rests completely on an analytical understanding, which can lead to a belief in fertilizing using mineral salts.


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If taken all at once, 300g table salt is lethal. The human body usually carries 150 to 200g table salt, of this 50g in the blood. Human beings with table salt deficiency become at first tired, weak, and indifferent.

In the Middle Ages and also historically, salt was produced from the ocean (salt gardens, appendix) or through evaporation of brine waters. Mining salt was one of the most expensive and dangerous of operations. While salt is now plentiful, until the Industrial Revolution it was difficult to come by, and salt mining was often done by slave or prison labor. In ancient Rome, salt on the table was a mark of a rich patron (and those who sat nearer the host were “above the salt,” and those less favored were "below the salt"). Roman prisoners were given the task of salt mining, and life expectancy among those so sentenced was low.

The ca 5 m high cooling towers that remain to this day in some continental health spas (such as Bad Nauheim or Bad Soden-Allendorf) were historically there to pre-concentrate the brine, and today nebulize the solution so that spa guests can inhale it. In face of the large need for salt in our time, which is largely met through mining, the question soon arises about the origin of those salt deposits. Simply forming by evaporation of ocean water provides the most common theory, which is not very satisfying.

The salt deposits seen today–like limestone strata–apparently formed through oceanic evaporates. A direct precipitation in enclosed bays however never leads to the observed quantity: 100 m of rock-salt layer would require initial depth of ca 6 500 m of ocean water. Therefore we assume that, for instance, the evaporation basin forming the central European Upper Permian Zechstein salt-strata, was at least periodically connected to the ocean by a shallow sand bar, so that more saltwater flowed in repeatedly. Many small cycles of static evaporation repeat themselves in the Stassfurt Basin: additional water must have periodically flowed across the bar; one must even assume on the basis of the breakdown of certain salts that periodically more concentrated solutions flowed back into the ocean since both oceans had similar elevations.

The arrangement of layers formed in this way should have contained more magnesium salts than are actually found, since the composition of the oceans has not changed significantly since the Cambrian. One subsequently formulates a metamorphosis of the solutions, e.g. changes in composition through circulating moisture. Nearby limestone rocks become ‘dolomitized’ out of solid salt.


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In any case, many concepts are uncertain: “A complete understanding of the processes involved is still far off” says a geologist.2 Did different environments exist during salt formation than exist today? An example for the bar-theory on a smaller scale is found in Lake Assal [west of Djibouti city by Ethiopia and Somalia in Africa, on the Gulf of Aden. It is an ultra-saline lake, lies 155 m (509 ft) below sea level in the Afar Triangle, making it the lowest point on land in Africa and the third lowest land depression on Earth after the Dead Sea and Sea of Galilee]. It has 32.4% salt content, about 10x that of the ocean. Four cubic meters of water evaporate every second, which are replaced by percolating ocean waters. Rack salt (halite) and gypsum periodically separate out.3 Noteworthy also is that precisely central Europe is underlain by extensive salt strata. The German Reich held the monopoly on potassium salts (used to make gunpowder) until the First World War (see appendix p. 38).

Important European Salt Formations (most related to the Zechstein basin, N. Germany, Poland):

Lüneburg—Celler Region, also called the "Salt Town" Friedrichshall—Heilbronner Region Schwäbisch Hall, Kochertal Stassfurth (near Magdeburg), Halle Salzkammergut (Hallstadt, Hallein) Oberrheintal-Oberelsass (Mühlheim-Mulhouse) Hildesheim-Braunschweiger Region (Salzdetfurth, Salzgitter)

Liverpool rose from a small English port to become the prime exporting port for the salt dug in the great Cheshire salt mines, and thus became the source for much of the world's salt in the 19th century

North American Salt Deposits:

The Retsof Salt Mine in finger-lakes region of New York, In 1994 the largest salt mine in North America, and the second largest in the world; between 1994-1995 groundwater entering the salt deposit, which had been dry for all of the 110 previous years of mining at the site mine, tunnels collapsed, and the mine fully filled with water

Windsor Salt Mine with two locations in Windsor, Ontario, Canada; mined approximately 9,500 kilotons from the Windsor mine, 85% of which went to deicing highways, and the remainder for manufacturing caustic soda and chlorine, producing pulp and paper, and water treatment.

Detroit Salt Company described as a “city under the city.” Extensive tunnels underlie both Windsor, and Detroit Michigan (road deicing salt is the only product the mine currently

2 “Salt Deposits, their Origin and Composition,” O. Braitsch, Springer-Verlag 1971 Translators note:

apparently in English! 3 Abriss der Geologie, Brinkmanns, Enke-Verlag, Stuttgart 1975, p. 47


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provides, ironic since ice-melter spread on streets in winter, severely rusts the cars, also made in Detroit)

Large, extensive salt deposits on earth mostly lie in the northern hemisphere. The Salt dome in Holstein is 65 km long, 6 km wide, 4 km deep. Scattered salt layers containing potassium and magnesium salts are often 400 m deep. Above this, for instance in Strassfurt, still lies 8m salt, 50m gypsum, and 200m young rock salt, overlain by gypsum,

World production 1981: roughly 172 million tons, e.g. around 0.1 km3, in 2000 ca 190 million. Miners call it rock salt, chemically the same as table salt (halite). Rock salt is up to 26% soluble in water at 20 ºC (26 g cooking salt + 74g water or 35.8 g cooking salt + 100 ml water). Density of this solution: 1.2 g/cm3, boiling point 107º, melting point of pure salt 801 ºC, boiling point 1440 ºC, crystallizes in the cubic (hex-octahedral) crystal class, the highest symmetry class. In pure form it is not hygroscopic (water absorbing).

II-5. FURTHER PEDAGOGICAL COMMENTS

Up to now we have fostered a more qualitative method. Sensual perception was focused on observable pictures and the pictures were compared through broad natural areas (salts/solutions). The concepts were exploratory and open. We tried to characterize in


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general the salt-like. Herewith arises more natural history, not necessarily chemistry. Of course one must approach chemistry this broadly if one wants to understand and not just systematize it. But in the students’ eyes, this is in no way chemistry. Some boys above all do not like this careful treatment of natural occurrences. They want disruption: that it stinks and bangs; that at least significant reactions are carried out and substances are created with unknown and powerful, also destructive properties.

The teacher must evaluate the class as to how far he may experiment in this way with the whole salts. Maybe 3 days? The observable and lovely experiments are often attractive to the girls. That one can quickly feel comfortable promotes confidence and participation. One will also have students who have difficulty with these simple and far-reaching thoughts that appear unimportant to them because they cannot bring any intellectual strength. Those with an intellect of closed sharply combined concepts find no area where they can be active and successful. The students then wish, for instance, for chemical formulas.

There exist very good themes—much better than formulas—to add more sharply contoured activities to this area. These are solubility problems, symmetry problems, and crystal drawings. I have often mixed these in with the other themes from the very beginning.

Salts, Acids & Bases Chap. 3. Quantitative and Geometric Themes

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GRADE 10 CHEMISTRY – MANFRED VON MACKENSEN (1988) CHAP. III QUANTITATIVE AND GEOMETRIC THEMES

III-1. TEMPERATURE DEPENDENCE OF THE SATURATION POINT

Every crystallization is tied to the whole system with more or less distinct temperature relations. Somewhat abstractly we can say: If a salt solution is cooled from the outside, one observes first sensible coolness and then the crystallized salt, whose appearance makes a ‘cool’ impression. And conversely: in warming a solution, the applied sensible heat brings about the disappearance of the salt-crystal with its cool appearance. Our experiment E7 also showed us that a solution, despite being cooled, never becomes pure water so long as we do not reach the lowered freezing point of water. These relationships are now worthy of further investigation with systematic experimentation.

Ex15 Solubility at Different Temperatures a. Stir 35 and 40 g finely ground table salt into 100 ml water at room temperature. The 35g

should totally dissolve, 40g may require some heating. Subsequent cooling the solution (placing in a beaker of cold water) causes precipitation of salt from the 40g solution.

b. We execute the same experiment with 30 and 100g of Blue Vitriol (CuSO4.5H20). The 30g dissolve quickly in cool water with clearly noticeable cooling (preparation for V17), the 100g dissolve just before boiling. During cooling, gradually increasing amounts of blue salt precipitate out of the 100g solution. The concentrations of the solutions are indicted by their color.

Ex16 Rate of Solubility

a. One student obtains a certain amount (maybe 10g) of large crystals of Blue Vitriol, and

another the same mass in powder. Each attempts to dissolve their material as quickly as possible by stirring into an ample amount of water (perhaps 150 ml). The winner takes less time, and the richer color settles the discussion.

b. The winner of the previous experiment is given a small amount of coarse-crystal sugar to taste, and then the same amount of powdered sugar and observes the difference in the development of the sweet taste.

On the next day we will determine that for each controlling temperature, the saturation of water, in which one has added an excess of solid, develops over time as follows:


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Only after stirring sometimes for many hours is the saturation point reached. In this respect we can’t expect precise results for our E15. If we consider the saturation point across varying temperatures, we obtain a curve for blue vitriol on one hand and cooking salt on the other based on raw experimental data. One can (afterwards) have them draw the curves more precisely using the values from the following table. With that it is enriching for the students to think among themselves about the units and numerical ranges for the axes of the graph.

The Solubility of Common Salts in grams salt / 100g water

Temp °C Table Salt

Potash Saltpeter

Blue Vitriol

Soda Saltpeter

Potassium Chloride

Potassium Iodide

0 35.6 13.3 22 73.0 28.5 128

20 35.8 31.5 32 88.0 34.7 144

40 36.3 64.6 44 102.0 39.9 160

60 37.1 118 62 122 45.5 176

80 38.0 166.5 87 148 51.4 192

100 39.12 246.0 120 180 56.6 208

SOLUBILITY OF VARIOUS SALTS AS A FUNCTION OF TEMPERATURE

One can discuss how the temperature dependence of the saturation point is one of the most valuable ways of producing the many salts that occur in nature as crust-efflorescences, as well as the rare salts that arise in volcanic deposits and are produced by re-crystallization of hot rock leachates. (The latter can take place in the lab lesson and is


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described in my booklet “Laboratory demonstrations and activities: Alcohol, Soap, Salt”, Kassel).

The question can also arise, how the lithified crystals like quartz and semi-precious stones have crystallized out. One must imagine here a formation out of hot, but not water free, rather gel-like liquids (not typical melts). These occur inside the earth under high pressure. Similarly mysterious are the up to 100-weight gold nuggets. They apparently develop mostly through unbelievably lengthy deposition of the smallest gold flakes from stream-waters of gold bearing granite mountains. Such gradual growth occurs in technology only with suction. Hydrothermal processes or imitation gel-crystallization. In the production of artificial rubies one has to deal with white-hot molten liquids and in the production of industrial diamonds with unbelievably high pressures and temperatures.


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If one compares the industrial processes, which we can scarcely imagine, with our lab experience of crystallization or dissolving, then we notice that we cannot enter into the true formative-language of the technical processes, because we cannot experience it directly [too hazardous]. The transition we have discussed, from the imagined to the crystallized state becomes only a mechanical conceptual abstraction. With this the language of forms completely transforms itself. One distances oneself further from an adequate comprehension of the total reality when observing the temperature dependence of saturation. – One is dealing in all these processes with two realms. On the one hand, with the realm of moisture, that gradually permeates all substances and eliminates all distinct concentrations; on the other hand, with the dry, isolated, individual kernel of salt. The mass-based perspective, data-tables, and graphical representations of saturation, as we have treated it, is one point of view that operates totally in the realm of dry, defined thoughts. It is conceptually sharp, and actually physical. This way of thinking alone again mirrors the dry field of salts! They remain one-sided in relation to the total appearance. [termed “earth thinking” by N Hoffman]

One will attempt to call forth in the students a feeling for the limitations of the quantitative observations. Then, when one solidifies what we have learned in the field [of experience] with practice problems of the following type, it will not lead to false conceptualizations: [termed “counterfeit wholes” by H. Bortoft]

1. Practice problem: 345g of a KNO3 solution saturated at 100 ºC are cooled to 20 ºC (see Ex10). a. How many g of the salt precipitate out? (213 g) b. How many grams, and what % of soluble KNO3 remains in the solution? (32 g, 13%)

2. Practice Problem: 264 g of a CuSO4 solution saturated at 20 ºC need to be changed into a solution saturated at 80 ºC. How man grams of salt must be added? (110g)

3. Practice Problem: To what temperature must a KNO3 solution saturated at 20 ºC be cooled so that of the 32g that are soluble, 19g will precipitate out? (0 ºC)

4. Practice Problem (difficult): The solubility of KNO3 is 50g at 57 ºC and 20 g at 22 ºC.

Now, following the outwardly controllable, we would also like to investigate the warmth phenomena which appear by themselves from within chemical changes and which quietly accompany not only all reactions, but also the mixing, separation, dissolution, and crystallization processes.


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A noteworthy aspect of salt chemistry is the sensible change in heat. Certain salts have a cool taste on the tongue. How is this demonstrated experimentally?

Ex17 Heat of Solution

We observe a temperature decrease (ca 1 C up to 10 C) that we can feel with the hands and measure with a thermometer when we dissolve 30 g of cooking salt and then 30 g blue vitriol or better KNO3 in 100 ml water. Using ammonium nitrate in water in a 3:5 proportion, one can achieve temperatures below 0 C and then freeze some water in an beaker that has been placed in it within 15 minutes.

Ex18 Heat of Fusion Insofar as it was not done in 9th grade physics, consider the temp-time curve for the heat of fusion for ice.

Ex19 Freezing Point Lowering Using the saturated table salt solution from E17, dilute 1:10, and freeze in bucket of ice/salt mixture. Measure freezing point. (Ice/salt mixture 6 parts crushed ice to 1 part table salt). The ‘sweet ice’ produced can be tasted by all.

Ex20 Boiling Point Elevation We measure the boiling point elevation of a hot saturated table salt solution. One can also add spoonfuls of salt to boiling water: foaming! The temperature rises correspondingly.

In later discussions of the experiments, the students may discover that a large temperature dependence of the saturation point is associated with a large release of cold during dissolution. Evidently, this cold, which is released during the dissolution of the crystal, varies in amount according to type of salt. This cold-potential originating from within the crystal can be associated—as already mentioned—with the overall cool appearance of salts. The phenomenon is such that the crystals with greater cooling-potential can only maintain their watery solubility at higher temperatures, when the solution is much more concentrated than at lower temperature. This ‘inner coolness’ does not influence the absolute saturation, but only the relative saturation, or increase in saturation. Blue Vitriol is


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temperature-labile relative to table salt. Its dissolution is more strongly dependent on environmental temperature, but it also influences more strongly the environment during dissolution. Table salt is more ‘withdrawn’ from the environment, more consolidated.

A few rarer salts or those with low solubility dissolve less in hot (boiling) water than cold, e.g. Li2CO3, CaSO4, Ca-citrate, CaCrO4, less so NaSO4 at 32 ºC. These salts warm the solution when they dissolve. In the freezing point depression and boiling point elevation we encounter the tendency already observed in many phenomena for salts to spread out in all ways in the form of solution. The water is thereby strongly absorbed; for even below the boiling point, at all temperatures, salt solutions always have a lower vapor pressure than pure water. Their ability to fill the air with humidity is therefore lower. There are even salts, which, once dried at higher temperatures and then cooled, absorb water from the air, become moist, and even liquefy, e.g. calcium chloride and magnesium chloride (hygroscopic). Beyond this, the boiling point and freezing point of solutions diverge to higher and lower values, respectively, than those of the pure solvent (boiling point elevation, freezing point depression).

The boiling/freezing point divergence of solutions can be understood through the properties of salts—generally: soluble matter, which in its solubility strives to further dilute and spread itself out. For, by boiling and freezing the solution, it is pure water that evaporates and ‘sweet’ ice that forms; this means that the solution would thereby become more concentrated. And it is precisely this which the fixed-point divergences work against.

With the freezing point depression the solution’s means of solidifying and becoming salt-free is hindered. In connection with this stands the property evident in all salts to pull the water necessary for dissolving even out of ice (melting effect of scattered salt). If one spreads dry salt on ice (cold mixture), the ice is forced to melt through the process of dissolution, and thereby both the inner cooling-potential of the salt and that of the ice are made use of; the latter produces the main effect.

The observed temperature and heat effects can be viewed together with the many other observed properties of salts, to dissolve, to dilute, and to distribute.


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III-2 SYMMETRY, TYPES OF CRYSTALS, MINERALS

In the Waldorf curriculum, R. Steiner indicated Mineralogy for the 10th grade. It is still partially unsolved how this subject is to be made a reality in the classroom: without lattice structures and without atomic bonding, and of course also without abstract geometric measurement like the Miller Index.

III-2B SUMMARY OF THIS CHAPTER:

The appearance of symmetry will be followed through the various natural kingdoms—the point of view becoming environmental openness simultaneous with assertion in the face of changing conditions. The elements of symmetry for crystals will be visually introduced in respect to the environment. Thereby sidedness becomes the lead-symmetry. With this the crystal classes can be newly arranged phenomenologically: unsymmetrical, parallel 2-,3-,4-,6-,and 12 sided family. The main crystallographic law will be visually presented by way of the higher platonic bodies. The elucidation of symmetry elements will be shown through selected growth forms of well known collected minerals. Connections will be made between symmetrical forms and chemical synthesis.

III-2C SYMMETRY IN DIFFERENT WORLDLY REALMS

The form drawing of the first school years gives us an entry. In simple forms we find only one line of symmetry (left, shown with a dotted line):

Other figures (right) have a center of symmetry, an inversion point: at the center of symmetry each line segment is drawn to the center and further until it reaches a corresponding opposite location (inversion). The newly formed figure, created through a


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specific symmetry-operation, has to be super-imposable with the original figure. Instead of an inversion, one can also rotate the whole 2-dimensional figure, not always other bodily forms, around the center: by 180º --also this can be super-imposable. Even more symmetrical is the following form (left), with which the symmetrical center is also a 3-count turning point. Rotation around 1/3 gives coverage; besides it has 3 mirror lines (symmetry lines):

Inversion, twice a mirror image on each line and two-count rotation: all this leads by itself to coverage in the right

ENCLOSED BODIES IN SPACE differ in their symmetry from these types of 2-dimensional drawings in certain respects. A crystal, which offers us at first perhaps a symmetrical view, reveals itself much less than the 2-dimensional drawing in which the whole figure always lies completely before us. In the 2-dimensional form drawings we see into the interior and oversee it all at once. Symmetry means here similarity of all parts, evenness, stamp-like totality—but without three-dimensionality. This symmetry leads to the orientation-symmetry of plants, flower symmetry etc. Also there we have the symmetrical arrangement of parts into an image.

A figure drawn in a picture has no relationship to an environment, rather a decided development of inner line-structure. With the crystal, in contrast, we experience the symmetry less strongly and clearly. We do not look into the structure, but can only study a closed off exterior. This exterior stands in relation to an environment even if we have not found the crystal outside in a natural setting.

One should investigate the symmetry of crystals less as a similarity of parts, as one is accustomed from studying lattice structures, than as an expressive presentation for the observer!


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We experience bodily symmetry in nature in a particular way. Let us consider for instance lawn bowling. A ball is tossed across a level lawn. It lands and then rolls along in a straight line exactly in the direction it was thrown. Its motion is even and smooth in all locations, it rolls freely forward. Even if one throws the ball a hundred times, it looks the same when at rest—for it does not have different sides. How different becomes the toss and the roll, when we throw a brick instead of the ball. During landing it tips and summersaults to the side, until it lies in any type of particular relationship to the surroundings.

The environment becomes an important foundation of our experience of symmetry: symmetrical bodies do not specialize themselves in the environment, they more or less hold themselves back from specific environmental relationships. The sphere as an object of the infinite conceptual realm completely withdraws itself from each case of changing gesture within opposed ordering.

The Sphere has:

• Infinitely many symmetrical surfaces, that take in to each other all spacial orientations

• Infinitely many to infinitely count-able ankles, e.g. rotational symmetry, that take in all special orientations,

• A center of symmetry

The chicken egg and the cylinder have, in contrast, fewer symmetrical infiniteness and such with limited angles; the 3-sided prism even less. (A foundation for single symmetry elements follows in the appendix on p. 44).

Cube and octahedron have highest symmetry, and both have similar elements: 4 three-count, 3 four-count, and 6 two-count axles, 6 similar and 3 similar (in total 9) mirror images as well as a symmetrical center. Without having to now search for each of these symmetry elements, one can experience that these bodies are largely indifferent to their orientation in the environment—one can toss them. An example is provided by the highly symmetrical crystal type called hexakisoktahedral which includes cooking salt, feldspar, mica, magnetite, diamond and many more.

Potassium-Feldspar, for instance, crystallizes in the ditrigonal-skalene class with the following symmetrical elements: 1 three-count and 3 two-count axles, 3 mirror images and symmetrical center. It can take the form of a rhomboid, bordered by 6 similar rhombi. One


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of the most elegant and ambitious crystal shapes is certainly the ditrigonal scalene shape; it is possible in lime-spar but de facto seldom fully developed.

In human beings we find only bilateral symmetry, one symmetrical surface (mirror image). Only in the iris appears the aforementioned rotational symmetry. The human body does not have a mirror image with respect to its inner organs but there is strong bilateral symmetry, e.g paired sense organs and limbs. With this the human connects himself to the outer world and acts with the environment together in space and light. In contrast, with the exception of the kidney, the inner organs especially the liver, gall, intestine and stomach are unsymmetrical in themselves and with respect to their location in the body. Of concern here are metabolic organs darkly acting in the body. Symmetry then enters into the realm of bodily function in acting together with the free or illuminated environment and in what one can experience acting in the environment (walking, seeing etc.). These functions are only given in complete union with waking awareness, they are in fact the stimulants and tools of enlightenment. In the digestive system on the other hand the human sleeps, his awareness there has healthily neither sensitivity nor influence.

Both these poles are also present in the nervous system. The central nervous system as foundation for perception and thinking is side-symmetrical in the distribution of nerves and the prominent brain regions. On the contrary, the autonomic system (sympathetic) is much more asymmetrical, especially the solar plexus. These networks are the foundation of the mutually “sympathetic” perceptions of the inner organs and never lie in the activities of our willful awareness.

In the rhythmic system, quasi between waking senses and digestive torpor, we find a partial symmetry. With this the largely inwardly oriented heart is only symmetrical in general structure and in the simultaneity of chamber motion. It lies somewhat outside the middle of the body, with its axis twisted around the vertical, therefore only slightly symmetrical. The lung on the other hand is more symmetrical—for it is exposed in breathing to free nature. On the outside, where it lies along the back ribs, it is totally symmetrical and only not so on the side laying alongside the heart.

In the animal world we also find the connection between light, the waking senses, and symmetry. So writes Wolfgang Schad about “the walleye and Glaswelse (a fish) from India maintained today in aquariums. The skin, the total sense-nervous system, the skeleton, the skeletal musculature and also the swim bladder are translucent, almost transparent. The abdominal organs however are sheltered from the light with a silvery, opaque surface, and


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only here are the asymmetrical organs found. The metabolic organs are not allowed to become active to the senses.”1

With the plant symmetry also appears in the parts of the organism, which belong to the free surroundings and turn themselves towards the light. Roots follow only the friable earth domain, wind themselves around stones and grow without strong symmetrical arrangement—however as they can progress amidst obstacles. The first Orientational symmetry appears at sprouting; e.g. the leaves of the stinging nettle are criss-cross from each other. With other plants like the rose we find placement taking the form of a leaf spiral (twisting). But all this is greatly exceeded by the symmetry of the blossom.

We encounter five-sidedness with the higher more differentiated flowering plants, e.g. rosacea. It appears even in the cross section of the stem e.g. the blackberry vine, can also pervade the entire plant. Five-sidedness was never observed in the mineral realm and is also impossible on theoretical grounds; as are all numbers higher than six.

A high point in development always demonstrates itself through symmetry both in the plant realm (placement-symmetry) as well as in the mineral realm (body-symmetry). In both natural realms the symmetrical forms are especially distinctive. Similar to the crystals in the lawless, whirling stones, the colored flowers lift themselves above the indifferent flowing green and point beyond their respective realm, to the higher. They indicate a developmental high point—but also preceded the ending. Lawless, unproportioned forms in contrast appear a motion closer, more suitable developmentally than bodies of symmetrical wholeness. The symmetrical has restrained itself, has become rigid. (A introduction to symmetry elements and their mineralogical application are in the appendix Crystal Morphology).

III-2D GRID PICTURES: DRAWINGS OF CRYSTALS IN SPACE

Supplemental to the natural descriptions and experimental observations we can approach the external crystal structure in mental exercises by engaging in dimensional drawing and symmetry studies.

1 Wolfgang Schad: “Man and Mammals”; Adelphi Press1971 / Adonic Press 2014,


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In order to discover the symmetries of the geometric bodies in which the salts appear and grasp them in the imagination, it is possible to work with so called grid pictures. In the event that projective geometry was practiced in the 9th grade, one would not need to add more in the 10th grade. But in order to make it clear, in which way crystal studies in the 10th grade can maintain foundation, be advised to enter more closely into such drawings. The following pre-exercise is useful, yes unavoidable, to understand especially the octahedron.

Every grid drawing consists of a layout plan, visual angle, and actual view.

a) The left shows the layout plan of a square grid (top view), on the wall similar to stepping-stones. In the middle of the grid section sits cube (dotted) covering a full grid. Outside the cube is drawn the direction locating the head of the viewer; and it is so far away, that its distance is large in comparison to the extent of the drawn grid section. This creates perspective. The “visual angle” drawing on the right shows how far the distance to the observer angles from the wall. One sees here (from the right) the wall in cross-section. The cross-sectional surface follows the dotted line of sight for the observer in the picture on the left.

b) The following view shows how the observer located in the layout plan sees the cube and the grid field surrounding the cube. Here can be seen how the grid and the cube would be foreshortened by the perspective.


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The angles and size relationships are drawn by estimate from the diagonal, so to speak until they look right. It should be demonstrated how the proportions can be altered by the movement of the observer. Important are the series of alterations, not the individually exact geometric drawings. (For more see appendix).

The unexpected outcome of such exercises is that one can never observe in a cube an exact right angle when one perceives its form in space, ie see at least three surfaces at once (widespread error in drawing!)

The student can ultimately feel capable of a spatial perception based on an exactly built image that is analogous to moving in the room around the cube. The cube then stops being a material object. It is the spiritual connection of a sum of views. Instead of the dimensional object one has the concept of a type of encounter in the area of pure sight without any basic matter. If one works through such drawings, one studies the still almost unconsciously reached conclusion regarding the basic body, that one otherwise misplaces in the world as the result of pure face value. One travels here the path from the conclusion backwards, from the relationship to the graspable image of the body to a constructed perceptual image. The concrete body is recognized as a product of our familiar thinking that is sparked unnoticed by the sense of sight and motion (following the contours).

It is not necessary at this point to point out further how necessary it is to become free from material objects, when on the other hand exactly at this point will be provided a chemistry lesson about the material, going out from the salt and salt crystal. Besides, through these drawings, one builds the ability to find symmetries in spatial imagination.

Salts, Acids & Bases Chap. 4. Acid-Gas and Base

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Grade 10 Chemistry–Manfred von Mackensen (1988) IV. ACID-GAS AND BASE

IV-1 The Effect of Fire

Ex21 Crystals In The Fire

A crystal of Copper vitriol (CuSO4·6 H2O) as large as possible and then a rock-salt crystal with an edge of at least 1 cm, are hung from a wire cage in the flame of a small wood chip fire or over a Fisher burner. The rock-salt crystal cracks after a while with a sharp loud bang. The vitriol crystal becomes dull on the surface, brown-green and in the wood fire hisses somewhat. Out of its’ insides bubble green pimples. After this it is no longer so soluble in water. If one hangs a twin crystal in the sharp flame of a burner, one discovers:

ü A shiny copper film below ü above it copper black ü above it basic sulphate, light brown ü above it ‘water free’ (anhydrous) sulfate, white ü above it ‘water poor’ hydrous sulfate, light blue ü somewhere remain dark blue places

In between are many blue-white pimples. Dark blue vitriol forms in the ‘axillary joints’ of the crystal parts, away from the flame. When it breaks apart one sees concentric layers from the outside inward.


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Ex22 Dehydration of Blue Vitriol

Gently heat a thin layer of Cu-vitriol crystals, placed in the bottom of a flask positioned above an air-space. Be careful to not overheat, because overheating speeds up the decomposition process, produces the acid-gas, and the vitriol will become brown instead of white. During heating condensation may form on the flask. So that water does not back into the flask, fan the outside of the flask with a second burner. After a while water vapor enters the connecting tube into the second flask. The blue vitriol becomes first light blue, then dark whitish and may jump about. In the middle of the connecting tube condensation water runs together. It should collect the vitriol dust being carried along. One drives it over by fanning it with the flame from the open end. After 5-20 minutes of heating, enough condensate has been collected and the flask can be removed. The first flask can then be heated with an open flame, so that its contents can completely change from blue to white (T> 200 C). In the meanwhile, one can test the condensate for smell, taste, and transparency. It tastes somewhat sour and bitter and should be distilled again to obtain pure water. Soon one can stir the now whitish-light blue copper sulphate and empty it into a beaker. The little seed-crystals of vitriol have become powder, which flies about during transfer.


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Ex23 Regeneration of Blue Vitriol One can take a knife-tip quantity of the whitish vitriol between the fingers and add a trop of water: immediately one feels a sharp heat. One adds water to the remaining vitriol powder (approximately ½ the volume of the powder)—heat and steam develop. Insofar as the powder is saturated with water, it changes to a blue color. Crusts that developed during heating cement themselves and can only be broken apart with difficulty. All this does not become wet, despite the addition of water; rather it remains dry and crumbly. Only additional water produces the familiar blue copper vitriol colored solution. If one heat the solution with the lumpy formations, it will produce pure copper vitriol crystals upon cooling. One can use the white anhydrous vitriol powder to verify the presence of small quantities of water: on a small portion we can pour pure alcohol. On another portion spirits of alcohol, which contain a percentage of water. In the latter case, blue color is produced.

E24 Complete Decomposition Of Copper Vitriol (foundation experiment)

A quartz tube with ca 11mm thickness (thicker tubes will not get hot enough) is filled with crushed blue vitriol or with anhydrous vitriol dust from E22, closed at one end, and and strongly heated at the open end optimally with 2 19mm burners. Soon as there is steam that gradually changes into heavy, stringy, sinking acid-clouds. We will test its cough inducement. White vitriol powder forms in the tube as in E22. Pale red and green colors form with this with further heating. (After a short glowing we also find dark green


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after cooling). With 2 burners we gradually succeed in a transformation to an ocher colored product and finally to a copper black, at least in spots. We then stop the heating process and empty the flask with water: a sharp sour taste. The differently icolored zones in the quartz-tube are arranged concentrically around the heating point.

Insofar as possible, separate the brown and black from the white vitriol powder, which we can determine all to be totally tasteless and insoluble after several hot washings to remove acid.

In the reflection over this experiment we can point out that crystals, in their entire formation and regular growth, have no up or down or inside or outside. How different from the open flickering fire! It cannot exist either in water or inside the earth, but only there where the air borders the solid. (We omit here glowing volcanic magma). One gets the impression that the cool salts crystallizing from watery solutions are not related to the flame. The flame strives upward and simultaneously ember and ash sink downward. This whole process is seminally entwined in the upper and lower reaches of the earth’s surface. In this respect it seems an artificial manipulation to put a salt-crystal into the fire. The large table salt crystal shatters (because of unequal heating), smaller ones slowly melt. The copper sulfate crystal loses its sheen, its clarity, and its solubility. Also its form is perverted. The resulting crystal becomes stone-like, earth-like.

After slight warming blue vitriol allows the release of steam. Already here it forfeits its solidity and blue color. The crystalline material falls to dust, which lets itself be easily regenerated. The white vitriol powder produced can take up significant quantities of water, without becoming wet. With blue vitriol we are dealing with a crystal with suction.

Crystal-water. A more accurate and truly phenomenological approach would reject the idea that there is water in the crystal. The crystal is dry and solid, not wet when broken, and also does not become wet when squeezed. We should rather develop the concept of incomplete precipitation from water during crystallization. Water becomes ‘frozen’ inside, even if the crystal forms at room temperature. The salt-crystal has ‘ice-nature’, when it forms a hydrate. Such salts, in contrast to table salt, constantly retain the ability to release steam during heating. Also thermally, vitriol shows itself as more labile. There are then salt crystals that one can disturb through small rises in temperature, that


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is, one can transform them into powdery ash. One could speak of “weak, water-connected” crystals in contrast to the water-free “true” salt crystals (table salt). Water-connected crystals can already decompose at normal temperatures (they become dull, white, and crumbly). The water vapor pressure for blue vitriol (pentahydrate) is 6 Torr at 20 ºC; water has 17.5 Torr at 20 ºC. If the relative humidity falls below 1/3, the vitriol can decompose; equally so if we warm ½ saturated air (9 Torr) at 20 ºC to greater than 25 ºC. –The blue vitriol has the mineralogical name Chalcanthite. It gives up to 36% of its weight to water (corresponding to the formula CuSO4 • 5H2O). At 100 ºC appears the light blue monohydrate, at 200 ºC the anhydride.

All vitriols separate themselves incompletely from water during formation. This binding of sulfate to water can be seen in connection with the water absorbing characteristics of sulfuric acid. Of course other salts besides the sulfates crystallize by way of water. The tendency toward hydration generally increases in the order nitrates, chloride, iodate, sulfate; besides it increases with the earthiness of the base.

The ‘schema’ with pathways of water loss for blue vitriol can be shown in the following way:


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Also the decomposition of copper vitriol by heating reveals its weak nature. The aggressive acid gas produced is a mixture of sulfurous acid, sulfuric acid, oxygen and in the beginning, water vapor. The clear, transparent, and well formed salt is thereby transformed on one hand into a smoky, labile and aggressive acid and on the other side a dark, dull, earthy mass that is no longer soluble in water. In this we have the foundation, the left over base of the salt—thereby the name ‘base’. The expulsion of the crystal-water is like a prelude to the complete decomposition with the same gesture:

The flighty water vapor escapes upwards, below remains lying the powdery anhydrate. The change in qualities for the overall reaction can be expressed in the following diagram:


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This diagram reflects the experience of the reaction with its intermediate steps and qualities; one takes away only the understandable material results. These are all transformed substances, meaning on one hand the used substances and on the other the newly formed ones, brought together from beginning to end in a flowing scheme. One considers with this the individual observations, the actual experiences, as if they came from the materials listed schematically, their appearance and disappearance, decomposition—a truly one-sided (if of course also typical) concept. Using substance names instead of qualities it then appears like this:

With such a pronounced vertical schematic one can only use diagonal, downward lines and not horizontal ones—because the disappearing substances are listed above, and newly formed ones appear below.


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IV-2 Important Acids

We come now to more focused experiments on selected acids. In so doing, we should still not strive to develop the overall rule: acids are made by oxidation of non-metals, bases from metals etc. This is a theme for 11th Grade. Here it would be abstract, since the analytical element concept has not yet been introduced. But with sulfur and copper, which were introduced qualitatively as substances earlier in the lesson, and which the students have already been exposed in their daily lives, should be shown the transition out of the solid, consolidated into the mobile realm of acids and bases.

Basically now one has the choice: does one cover acids first or bases? In favor of bases is the following:

ü the bases are the simpler decomposition product, because they are solid and physically at hand.

ü they are simpler and visually distinguishable (color, solubility, flame color) ü the experiments with acids have more costly equipment and are more

spectacular—they serve as a good build-up.

Nevertheless I like to do acids first. They have a stronger presence in all their effects –influence the environment more than the restrained, earthy bases. The acids disperse themselves as characteristically smelling clouds in the air. They are often aggressive and react in all directions. The subconscious question of the students, who through their experience with the decomposition of salt in fire saw that all things can be made or developed into something new, discovers through investigations of different acids a richer answer that stimulates further interest.

Sulfuric Acid The typical school method of catalytic oxidation is described in the appendix, but should at best be first worked through in the 11th grade since it is comprehensive and can distort the lesson block development. Simple and impressive in contrast is the creation of acid gas by burning in the open. One can suck it through water and produce the liquid acid. Then one shows the characteristic effects with the industrial, oily acid, which is produced through intensive burning and evaporation. But beforehand one can ask, with


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a 7th Grade workbook obtained in a timely fashion, which experiments were perhaps then already demonstrated.

Ex25 Characteristics Of Sulfuric Acid

ü When poured, oily, viscous ü Buoyancy test (similar to E5 b) ü During boiling: low volatility, swirling gas movement in the test tube or flask;

sharp odor deep in the throat, induces coughing. ü Dripping boiling sulfuric acid (from C) onto organic substances (wood, linen,

flour, sausage…) : immediate etching and sizzling.

Ex26 Diagnostic Reaction

a) The formation of gypsum with calcium chloride serves as evidence of sulfuric acid (barium chloride would serve as another salt in this lesson, with which we would see additional elementary effects which we do not with gypsum). One prepares 1 liter of clear 50% calcium chloride solution (500 g CaCl2 · 6H20 + 500 g water) that will also be used in other experiments. We fill a larger beaker with a 1:10 dilution of this solution and sprinkle a 10% sulfuric acid solution over the top: in minutes slight darkening, gradually fine crystal sheets that stick together during precipitation. Precisely this gradual formation of such a precipitate should be experienced. The method of testing will become evident later. One can also sprinkle solid, glassy, whole crystals of calcium chloride into diluted sulfuric acid: whitish surface film, whitish solids on the bottom.

b) Also possible is precipitation with concentrated sulfuric acid and saturated calcium hydroxide (freshly slaked, cold leached calcium oxide): after warming, fine flakes on the next day. This experiment is didactically better, since it easier to explain than with calcium chloride.

Ex27 Dilution Explosion (please determine yourself whether this should be

carried out) Into fuming sulfuric acid drip water through a 2 m glass tube (wall thickness at least 8 mm) (cover surroundings with newspaper): first sizzling, then explosive boiling,


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spattering with smoke trails, huge mushroom cloud; later it goes out in cooking bubbles. (The class must immediately be evacuated, and later neutralized with ammonia vapor. Impressive experiment which is probably in accordance with regulations in only a few countries). [Bet D]: Use a large diameter test tube, 6 inch long. Fill with 10-15ml (3/4 inch) of H2SO4. Put into a clamp attached to a ring stand. Cover with a small watch glass. Heat while holding the burner and moving it around the liquid. As soon as see even one bubble of boiling, stop the heat. Then quickly drip (turn on full bore) from a separating funnel with a 2 ft tube attached.

Sulfuric acid causes destruction of all natural objects, carbonizing and destroying. There is nothing created by living things that would not be dissolved sooner or later by sulfuric acid. From bones what remains left over is at most small quantities of formless slime (plaster). Concentrated sulfuric acid can never exist in nature, as it dilutes itself when exposed to air in a few weeks from 30 to 40% by taking up water vapor (in an average relative humidity of 55%, corresponding to the climate of moderate zones). Dilute sulfuric acid appears in some hot springs in Nueva Granada, Tennessee, and Java, ostensibly as a product of the exposure of overheated water vapor to iron vitriol. A spring in northern Texas contains 5.3 g sulfuric acid per liter (Rudorff). Free (liquid) sulfuric acid was observed in a sulfur and plaster grouted sand in the Karakum desert east of the Caspian Sea. The production of sulfuric acid as the foundation of the chemical industry (see my booklets: Chemistry lessons for the 7th and 8th Grades) is enthusiastically written about by W. Greiling, although with excessive trust in progress: Chemistry Conquers the World, Econ-Verlag Dusseldorf O.J., 1964.

Mnemonic: all salts, from which one can make sulfuric acid, are named sulfates. Sulfuric acid is “sulfate acid”.

B. NITRATE SALTS AND NITRIC ACID

Ex28 Decomposition Of Nitric Acid

In a large test tube, add a crumb of activated charcoal to melted and boiling (decomposing) potassium saltpeter. It glows and dances on the melt.. A small piece of sulfur flames up beautifully, and produces a cloud of sulfuric acid. Aside from these


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components of gunpowder one can test pieces of wood (from matches), sugar, wool, etc. Other nitrates, e.g. calcium nitrate or copper nitrate, can bring about similar flaming.

Ex29 Making Gunpowder (As a simplified experiment: sugar cane and saltpeter in 1:1 in volume.)

One mixes the following, finely pulverized ahead of time. As soon as sulfur has been added use a plastic spoon, cardboard strip, or a goose feather to avoid rubbing, heating, and bumping of ingredients.

1. 16 g of saltpeter and 8 g of charcoal powder dried at 110 degrees ºC: 2 + 2.5 lightly heaped teaspoons. Rub together at least 1 minute, ideally long enough until everything is evenly gray. To test, light 1/8 of this; sometimes it goes out.

2. 16 g of saltpeter and 8 g flowers of sulfur, 2 + 2.5 teaspoons. Light 1/8 of it, it always goes out. 3. Thoroughly mix together the remaining mixtures from 1 and 2 in a beaker. Light 1/3 with a match. Flames up within seconds. 4. Mix the remaining mixture from 3 with 3 ml water to make crumbs. Dry this mixture for approx 20 minutes in a larger ceramic saucer, periodically breaking up the clumps (while doing #3) over a low burner with an asbestos pad and 1cm overlying air space. This mixture can flare up in extreme cases. If it gets hard and crusty, remove from the burner, break it into pieces, and resume drying. Light up ½ of the mass; it should flare up and burn more suddenly than before drying. 5. On an asbestos or iron plate, mound the other ½ of the powder from #4 in such a way that the flame runs along the edge of the mound and pops up through a board from underneath. Light with a glowing cigarette.

Nitrates are easily soluble, especially meltable, and act as strong oxidizing agents. In this respect they are poorly consolidated and unstable. One does not find them on earth in deep-lying salt mines, rather only near the surface (Chile). In India, after the rainy season, saltpeter can wick to the surface of potassium-rich, well fertilized soils. Besides this one is familiar with the surface wicking of ‘masonry-saltpeter’ in animal stalls. Saltpeter salts appear then at the border between the solid and the air. The ammoniacal animal excretions are created in connection with mobilized protein and


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protein breakdown in the organism (compare to characteristics of protein in my 7/8 grade chemistry book). The decomposition of liquid manure in air and the subsequent reactions of ammonia that follow in the ventilated barn walls lead to calcium nitrate. For more information, see appendix on saltpeter deserts and saltpeter production.

Saltpeter is created in a similar way in aerated soil. A connection between saltpeter formation and atmospheric processes is also evident in that rain and snow carry with them highly diluted ammonium nitrate.

The relationship to the moving air element is especially evident in melted saltpeter: the saltpeter can replace the oxidizing potential of the air, acting like a concentrated, mineralized air. One should make clear to the students that gases were constantly being released from the test tube, inclusively sulphur crumbs were being hurled out so that nothing could move in. (1 cm3 of saltpeter produces at most 1200 cm3 of oxygen.)

With the explosion of gunpowder, whose destructive effect is accompanied by development of large quantities of gas, we experience impressively the return to gaseous state. The main reaction is indicated as 4 KNO3 + 2 S + 6 C -> 2 K2S + 2 N2 +6 CO2. With humid air a breath of hydrogen sulfide forms, which arises as a smelly component of gunpowder smoke:

K2S + H2CO3 > H2S + K2CO3

One gram (=0.6 cm3) of black powder yields empirically approx 280 cm3 of gas at 0 ºC, but in fact when burned at temp of 2400 ºC about 10 times that. In bombs pressures up to 3000 atm are produced in this way. All nitrates can be used for powder mixtures, however copper nitrate and masonry-saltpeter Ca(NO3)2 • 4H2O need to first be dehydrated. If one lets the saltpeter from the gunpowder solution in E35d wick up onto the porous, surface rich coal and flower of sulfur, then the mixing of substances is amplified many fold and the subsequent reaction runs faster. This principle is driven to the extreme with guncotton, trinitrotoluene and nitroglycerin: nitrate and combustible materials are even bound to each other on the inside (chemically) and completely permeate one another without having reacted with each other already in a fiery way (see 11th grade).


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Ex30 Decomposition Of Calcium Nitrate

At the beginning, with gentle heating, calcium nitrate liberates large quantities of water vapor, so it ‘melts,’ so to speak, in its own crystal-water. With further heating it emits all its crystal-water and is momentarily arrested foaming. With the heat turned up, it truly melts (to some extent), and a toxic brown smoke is produced (various nitrous oxides–USE VELTILATION). One carefully washes the ‘smoke’ through water (color developed with indicator), establishes the sour reaction with indicator, and shows the alkali reaction of the remaining ash–base, by rinsing out the container with distilled water. The glass wall has become etched in spots by the caustic chalk.

Ex31 Diagnostic reaction of Copper with Nitric Acid

Dip a thin copper foil that has been cleaned with cold nitric acid into boiling hot 15% nitric acid (1/4 dilution of ‘concentrated’). There appears the familiar brown cloud, holes in the copper, as well as blue-green color in the foaming solution.

Ex32 Fuming Nitric Acid Fill large test tube ½ full with possibly 100% nitric acid and heat it (goggles). It releases brown gas: nitrous gases, oxygen, nitric acid vapor and a little water vapor. We dip a glowing splint into the gaseous portion of the test tube: it flames up and creates large quantities of brown smoke. Upon removal, the gas is momentarily less brown.

The oxidation potential and volatility of nitrate completely overwhelms nitric acid, even intensifying itself since the consolidating base is missing. Concentrated gas is not


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stable, and decomposes in part to oxygen and reduced nitric acid (brown nitrous gases). This decomposition is sped up with the heat from the flaming splint (more brown gas). After the expulsion of the latter, the air in the tube is momentarily enriched with water vapor, so that the following nitric acid vapor is concentrated instead of decomposed. If one guides the nitrous gases together with oxygen in water, the nitric acid is re-formed. The sudden emergence of the almost threatening brown gas is just as amazing as its quick disappearance, which shows the changeable nature of nitric acid in contrast to sulfuric acid. The fumes then serve as evidence (for the time being only of the acid, not yet the nitrate). One can at this point easily avoid any basic discussion of nitrogen and nitrogen oxides. This should be left for the element studies of the 11th Grade. Here the acid is not characterized through the element, rather through its origin in a particular salt-family.

A salt of reduced nitric acid is produced by melting nitric acid, just as it is temporarily in the decomposition of calcium nitrate. This creates a type of labile precursor of the fully oxidized acid and addresses the relationship between the sulfurous and sulfuric acids. If one desires further clarification of this reaction, one can consider the following reaction scheme:


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Mnemonic: All salts that can produce nitric acid are called nitrates. Nitric acid is nitrate-acid.

Hydrochloric Acid

Ex33 Hydrochloric Acid Through Decomposition Of Calcium Chloride

Lime saltpeter (CaCl2 • 6 H2O) is heated in a large 30 x 200 mm test tube just as the calcium nitrate was above in Ex30. First water condenses in the collector, then a sharp smell is perceived. A bit later one swirls the collector out with water: acid (taste and pH paper); residual: base-like. The acid produced is more meager than that from the same experiment with potassium nitrate.

Ex34 Determination Of Hydrochloric Acid

One places a drop of concentrated “hell-stone” solution (silver nitrate) on a callous of the hand: after hours appears a black spot—therefore the name ‘hell-stone’ . (It wears off in the course of a week). Now one prepares a larger quantity of very dilute silver nitrate solution (ca 0.1 g per liter). It is difficult to obtain enough demineralized, meaning chloride free water. In the weakly rotating solution one drips the acid from E33: quietly spinning veils, delicately floating downward. The cloudiness becomes gray-violet in ca ½ hour. One adds hydrochloric acid to more concentrated silver nitrate solution (ca 10g/liter): cheesy precipitation. Place ½ the precipitate in the light, and the other half in a dark cupboard and observe the next day (latter remains white).

As possible decomposition products of silver nitrate we propose the following scheme:


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Ex35 Synthesis From Table Salt

The cooking salt foams with the addition of sulfuric acid drops, and large quantities of transparent invisible hydrochloric acid vapor are produced, that forms fog in the moist air of the room. In order to make the experiment visible, one can add a larger stone-salt crystal; one will observe later, how it has changed. We test the produced acid gas for smell and flammability and direct it into a round flask. After a while it overflows. Inside the acid gas is fairly clear, but when it overflows it makes a fog. One fills a second round flask. With the first one, one shows that fog appears when we pour in water, and suction when we subsequently swirl the water around. The water has become acid; and this acid does not let itself evaporate.

E36 Hydrochloric Acid Fountain

One closes off the second flask filled with hydrochloric acid gas (or evaporated from concentrated hydrochloric acid) with a single-hole stopper filled with a glass tube and inverts it into a large container filled with water containing indicator. The water shoots into the flask at first slowly, finally spraying past the rim of the outer container, and the indicator changes into an acid color.


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E37 Stomach Acid In conclusion we allow tasting of a “stomach acid” of 0.4% (average concentration).

E38 Displacement Of Acid

a. In a large test tube, pour concentrated sulfuric acid (testable with calcium chloride) onto saltpeter and heat. The expelled nitric acid vapors are identifiable by their brown color. One can make this more visible and impressive using a retort. Practically anhydrous nitric acid, useful for E32, is produced.

b. Dilute hydrochloric acid (testable with silver nitrate) is poured onto a carbonate salt. The rising carbon dioxide can be identified by suffocating a match flame, held inside the beaker. The table salt produced by soda can be determined by tasting.

In the discussions following the experiments one will emphasize the special character of hydrochloric acid. It is produced by heating only less stable salts, that have not freed themselves entirely from water, and not from bringing the very resilient table salt to a glow—from this it is first produced by exposure to and usage of sulfuric acid (one can also substitute phosphoric acid). These reactions become more apparent in regard to the “Acid Series”.

Hydrochloric acid holds the middle in its volatility between the easily volatile, not with water combining carbonic acid and the oily, also without water readily liquid sulfuric acid. Once in the water, hydrochloric acid exerts an intense hold (condensation point: -85 ºC). More dilute or concentrated solutions arrive at 20% acidity following boiling. The solubility at room temperature (20ºC) under a vapor pressure of hydrochloric acid of 1 atm consists of approx. 450 L acid gas in 1L water (ca 42% by mass). In common usage is the so-called ‘fuming’ with 38% by mass; when there is not 1 atm pressure of acid gas over it, it expels this. The bottle is now filled up. By opening and decanting the acid the acid vapor, which is somewhat heavier than the air, flows out and forms with the air moisture the familiar fog (the so-called fume). Its tendency to form salts, connected with volatility makes hydrochloric acid a dangerous rust starter. It is all-pervasive in the air. Through its ability to condense it deposits itself on all surfaces. One can place for instance a clean, rust-free piece of iron near a small bowl of hydrochloric acid under an inverted glass.


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It is difficult in E35 to observe the creation of a new type of salt (sodium sulphate) and the disappearance of the sulfuric acid. The formation of both is incomplete, even at the boiling point, eg only until NaHSO4 and not demonstrable in the current reaction (and the treatment of acid salts would be confused). Nevertheless the correct reaction scheme lets itself be worked through based on the opportunities of the salts.

To conclude the treatment of various particular acids, one can present the following Volatility Series of Acids:

Carbonic acid (sulfurous acid) Hydrochloric acid Nitric acid Sulfuric acid (Phosphoric acid) Silicic acid = ‘lithified’ acid

IV-3 Important Bases Ex39 Melting Table Salt

In a quartz test tube (16 x 160) add table salt (3cm full) ) is heated to a glowing molten mass with two strong burners (Teclu 19mm) in a room darkened as much as possible. No ‘smoke’ arises; no smell is perceptible at the mouth of the test tube. Above the molten mass, when we survey the whole test tube wall, a delicate ring of sublimated salt forms. We pour the melt onto a clean pan or heat-resistant saucer: often cubic fractures in the solid.

Hydrochloric acid (literally “salt-acid” in German) has its name for a reason. It arises from the most stable, widespread salt, table salt, and also serves in its symmetry as an archetypal salt. It cannot be decomposed by heat alone, so we can not show the sodium-base. [see also: caustic soda and chlorine gas production, by electrolysis of molten halite, a major chemical industry.] However it is known that this base-stem can be obtained by decomposing ‘Chile saltpeter’ (Na NO3)–That this is the same product we will soon be able to show through salt displacement. The instability of the nitrates, which we just experienced, makes them very useful [explosives].


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Ex40 Production Of Caustic Soda (Duration 20 Min) In a super heat resistant test tube (7 X 70) add only one cm height Na-saltpeter (NaNO3). It will be melted, and with maximum heating gradually decompose. Oxygen is released, which one can show with a glowing splint. The quickly decanted and leached residue will prove itself to be a strong caustic base. Fingers become immediately slippery as ‘digestion’ is initiated. It causes a burning sensation on the tongue, wounding commences. In the flame it makes an enduring yellow color (sodium traffic lights). Potassium nitrate works here also, but reacts more slowly.

Ex41 Caustic Soda And Water

Place dry caustic soda (soda ash—K2O?) in pill form on a petri dish and expose it to the air for a few minutes: the previously easily rolling pills are moist and stick together. If we could have taken them safely in the hand before, they now have become caustic.

With broken pills, one can show the high solubility that is connected with strong warming. If the basic solution is not too hot or concentrated, one can filter the slight dullness that usually occurs because of the glass or poor cleaning; otherwise, leave it to precipitate.

During later efforts towards conceptual understanding of the experiments one can point out the difficulties that confront the isolation of caustic sodium and caustic bases. Precisely the bases, that are highly soluble and with which one can carry out many reactions because of their aggressiveness, are difficult to produce. The isolation through saltpeter displacement would not be commercially possible.

An old production error of soap makers for the necessary caustic soda, called soapstone, was the so-called activation of ash-solutions. If one layers ash for instance from seaweed in alternating layers with burnt lime (CaO) in large vats, the ash solution reacts with the caustic chalk as it percolates through. The latter is changed to limestone, and the solution thereby loses thereby its carbonate. The activated solution collected in a straw layer at the bottom of the vat, was used for enrichment in subsequent vats of ash and burnt lime. Another poorly producing source of caustic soda were the Natron Lakes in Egypt; but this was mixed with carbonates, which had to


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be activated with caustic lime. How this activation works will be discussed later. Also the modern errors in caustic soda production and the soda industry should –if at all—be discussed a few days later (after the acid- and base-residuals). They can then be partially rediscovered by the students. We show the following experiment only if it has not yet been brought in the 7th Grade.

Ex42 The Lime Base

Burnt lime, lime ash (Ca0) as produced in the 7th Grade, is sprinkled with a little water. The warmth and steam evolved (only with freshly burned) discloses an intensive reaction, which one floods with a lot of water and then filters, only to find, amazingly, that practically nothing has dissolved, since the amount of residual on the filter paper is similar to the amount of burnt chalk we started with. If we take a sip of filtrate in our mouths, we notice the characteristic sharply rotten taste we experienced in E24; an indicator shows an alkaline reaction (pH 11.5-12.0 theoretically 12.3).

Ex43 Test for Lime The lime base can be identified when dry by its yellow-red color in the flame test (magnesium ribbon cleaned and moistened with HCl), but sodium has to be eliminated (try it!). For alkaline lime solutions it is typical that they produce a haze and a precipitate when we blow (exhale) into them; notwithstanding their pH and their taste.

When considering the experiment in the next day’s discussion, one can indicate that we have before us in the lime base (burnt lime) a substance which is neither soluble nor insoluble (1.2 g Ca(OH)2 per liter) . One refers to it as slightly soluble. To dissolve one teaspoon full, one would need a bucket of water. Gypsum, long declared by us as insoluble, has a similar solubility. Also the apparently insoluble precipitates almost always have slight solubility. In order to determine this more precisely, one would need to evaporate a large volume of the dilute solution.

The slightly soluble burnt lime belongs to a special group of bases, which are barely soluble in water, but can still make weak basic solutions. To this group of so-called Alkaline Earth Bases belong also Magnesium and other unusual salt-ashes (strontium oxide).


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A second large Base Group is made up of the heavy metal bases for example rust and copperblack. They also have an ashy looseness and are unstructured, but in contrast to the Earth Alkali bases, heavier, mostly earth-dark in color and completely insoluble. The bases in this group occur in nature in pure form, but almost never produce well- formed crystals. They form mostly flaky precipitates from solution. Salts, that have the ability to form these types of bases, are easily disturbed during simple dilution—the base is formed, but still with almost unearthly fineness, still very spread out, hovering (Hydrolysis).

Ex44 The Copper Base Shiny copper can form a flaky skin of black copper-ash through burning, that is the same as the base in E24. Its insolubility was shown there. For proof the color could be enough. Or we take a good knife-tip of copperbase on an old metal spoon, heat it and dip it glowing into methanol (if necessary spirits): a copper colored layer is produced on the base. Also the flame color is typical (with HCl): concentrated blue, then green.—If one mixes 2 volumes copper nitrate with 1 volume sugar and manages to bring it to a glow, then here is also produced a copper colored coating on charcoal.

Ex45 Hydrolysis

Saturated sulfur solution is dripped into a large volume of water on a light table: veils, haziness.

Ex46 The Iron Base

Also with iron base (rust, iron-ash) it is not possible to bring about solubility. To verify rust we heat to glowing a small portion in a metal spoon and let it cool: red-violet color.

Ex47 Base Displacement (J Petering)

a. A few drops of the soda-lye solution (NaOH), made in the preceding experiment, is added to calcium hydroxide; the calcium base falls out. b. Into 40 ml of fresh, sharp calcium hydroxide (pH12), we put in about 5 drops of


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saturated copper chloride solution. Usually we see copper-base sink down forming a blue, loose layer of gelatinous 'floc,' which after short heating becomes black-brown. (try it out ahead of time) c. Soda lye (sodium hydroxide) reacts the same way with copper sulfate or copper chloride solution. With excess soda lye: a darkening of the gel, already without cooking. Beautiful color changes.

An especially beautiful and characteristic experiment to introduce iron-base is provided by the following experiment.

Ex48 The Color-Play of Iron Base

A day ahead of time, we prepare 1-2 liters of 1% sodium hydroxide solution, then cook it (to remove the dissolved oxygen), cool, filter and store it tightly closed. In a flask on an illumination-apparatus1 we swirl this liquid into a gentle vortex, and sprinkle in crystals of ferric nitrate (iron III nitrate) in the center; gradually rusty-red flakes sink down and ball up into an almost blood-red color on the bottom.

To explain the experiments with bases we work out that all the salts—including the lithified, nearly insoluble ones (ex: limestone)—apparently have within themselves two possibilities of forming something new. If one of these possible substances arises, then simultaneously the second always will, and the salt disappears. The salts differentiate themselves according to the possibilities. Their rational names are formed from the possibilities. Thinking in terms of invisible possible products is typical of chemistry. One will think through which particular characteristic of a given salt will be found again, metamorphosed in a specific base; for example, color becomes darkness, stability of the alkali salts becomes solubility of the base, easy decomposition of the metal-salts becomes insolubility of the base.

1 Illumination Apparatus: a wide paper box, whose height matches a metal tripod set inside (prop it up if necessary to match the carton) is given a circular opening sized to match the inner hole in the tripod top. There on top, we can set a large Erlenmeyer flask or beaker (2 liter wide form, or 5 liter 'high form'). Inside the carton, we have a 200-W light with reflective layer underneath (aluminum foil)


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The last experiment shows base displacement. It corresponds completely to acid displacement. With these displacement reactions, the milieu plays a great role (the stron acid and/or base) particularly to make solubility less possible. Displaced acids often disappear as gaseous formations in the air; displaced bases form insoluble precipitates and are returned to an earth-like state (exceptions: silicic acid and ammonia). As we organized the acids according to their volatility, we can arrange the bases according to their earth-relatedness (low solubility). In this sense, we can distinguish three groups:

1. The Alkali Bases–highly soluble, aggressive: sodium- and potassium- etc.

2. The Alkaline Earth Bases–only weakly soluble, for ex: calcium hydroxide, magnesium hydroxide (transition to the earthy bases) and strontium base (transition to the alkali bases).

3. The Heavy Metal Bases, earth-like, completely insoluble (iron, copper, etc).

The neutralization of acids and bases produced by industry and in our laboratory, and that are poisonous to the environment, should also be mentioned (underground lime in relation to carbon dioxide in the air; threat of industrial acidification with pure granite underground as in Scandinavia)

The word base should already be known since 7th grade. It derives from ‘basis’ and emphasizes that in salt decomposition the base is not volatile, but remains, like the ‘base’ underneath the columns of a Greek temple that remains even after earthquakes and other disturbances. Except that the column base, or a building foundation, is already there before the destruction, a visually defined part—the base of the salt never is.

IV-4. GENERAL CHARACTERISTICS OF ACIDITY AND ALKALINITY

We are coming now from the individual acids, whose characteristic properties are evident especially in concentrated form, to consideration of general acidity. This does not exist in pure form, it is always tainted and subverted by the special properties of


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individual acids; and least of all when in diluted form. First we can insert the following experiment to demonstrate general evidence of acidity through taste and pH paper.

A pH Scale and Values

Ex49 Dilution Series Of An Acid We start with diluted sulfuric acid (1N, or 5%) with pH 0 and dilute by factors of 10; ie 10-1, 10-2 etc. so that pH values of 1.2 etc. arise (see footnote *). Using tapwater, which is typically buffered by carbonate, the pH scale jumpstarts to pH 4, with demineralized water it is more precise. We then test the sour taste: dilution limit pH 3, at pH 4 to 5 one can still taste the difference with water, but one does not know what it is. At the same time measure with indicator paper e.g. Lyphan 1 to 14 and eventually with cabbage juice. Alongside (at pH 2) one makes a two-fold dilution for testing: no distinct difference in taste or pH value (argument for the 10-fold scale, and logarithms!). For more about using pH papers at neutrality and about plant indicators, see appendix.

NOTE: The justification of starting with diluted (but still sharply sour) acid and not the concentrated one lies therein that we are not investigating properties of the acid-part—e.g. the water absorbing capacity of sulfuric acid, or the oxidizing capacity of nitric acid—rather we want to observe the persistence of the acidity per se during dilution; therefore we start from an unspecified point, namely the diluted acid.

We find ourselves in the same situation as the neutralization-analytical working chemists in the middle of the 19th century (e.g. Friedrich Mohr). In order to free themselves from the peculiarities of the then ubiquitous acids—whether hydrochloric or nitric etc.—they had to ignore the varying masses of the acids. Instead of a mass-based concentration they focused on a purely intensive measure and named it ‘Normality’. Acids have the same normality, when they, despite different mass-based concentrations—equally neutralize any known alkaline solution. (Normality = “alkali-neutralization-ability”). This can be made understandable to the students, and it does express a universality for acidity (and alkalinity). In addition the teacher may want to consider that the ‘accidental’ beginning concentration of our pH scale–5% sulfuric acid for pH =0 – depends on agreements for the mole: insofar as the formula mass of hydrogen was fixed at 1 gram through Dalton. To work through the concept of


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normality, then, one does not need to fall back on discussions of numerical values and especially not on particle theory.

On the next day, one focuses with hindsight on the dilution series where red cabbage and indicator paper, first of all, can determine the concentration of acid and base without reacting to the peculiarities of the acid. Secondly: they can also make the determination where one can no longer taste anything. In theory, one could verify these dilutions by evaporating the water and weighing exactly.

So one comes to a dilution of 10-6 mol/liter and (for a monobasic acid) a pH value of 6. Another ten-fold dilution with the purest of water leads to something unexpected: for this dilution does not have a 10-7 concentration of acid (pH 7), rather of around 1.6 x 10-7 (pH 6.8). This is because the water on one hand functions itself as a weak acid, and on the other hand “swallows” (buffers) practically half of the acidity of this so far diluted acid. And water is of course also its own weak base. A 10-6 M of a simple strong base (e.g. NaOH) have a pH value of 8. Also here, for the same reasons, subsequent dilutions do not lead exactly to calculated results. A further dilution of acid, to reach the pH-value 8, is useless: it goes asymptotically away from 7; equally so with the base. So, strongly diluted acids and bases are the same! (e.g. in the color reaction to red cabbage, when one dilutes from pH 6 through one or more factors of 10). The acid-(base)-part lets itself be further diluted—its acid individuality disguised—not the acid and alkali quality.

If one increases the concentration of acid or base, we theoretically get a pH-value of 0 or 14 at 1 mol/liter. In practice however there are strong deviations due to activity-coefficients! In the long run the pH-values follow the negative 10-factor logarithms of concentration. From the electrochemical viewpoint, we are dealing here with the hydrogen ion concentration (precisely—activity), and with the mentioned buffer effect of pure water because of its self-ionization. The pH-value is therefore a measure for the approximate acid or base strength in factors of 10; one step represents a dilution or enrichment of 10-fold.

Conclusions for the students: the pH-value of distilled water and neutral solutions is set at 7, and that of a diluted (ca. 10%) acid is then 0. Each unit signifies a change in


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concentration by a factor of 10. The pH-value also determines the negative logarithm of the concentration of the diluted (strong) acids. With dilutions greater than 10-6 (> pH 7) the acid individuality disappears completely in water.

The lesson can be solidified with the following type of assignment: a sulfuric acid solution with pH 2 needs to be brought to pH 5 (or 0). How much water must be added? Aside from mastering the quantitative there is however another different observation that is valuable. With the clearly understood pH-value-numbers one has a squeaky-clean structure with which to easily negotiate dilution series encompassing billion-fold differences, without having to be careful about where one actually is. And that is what it is all about. The ten-fold steps of the pH scale are in fact like seven-mile boots, and one discovers, with some inner reflection, what an immensely huge range the acid has in the world—how it is active in the finest dilutions of life-fluids and how at highest concentrations it can bring about brutal reactions in thick walled flasks.

IV-b. Strong and Weak Acids—Buffering

Further experiments can lead to the perhaps surprising insight that the general effects of acidity only show themselves when water comes into play.

E49a Sulfuric Acid And Nail, Formic Acid and Magnesium Ribbon

Fill a test tube half way with concentrated sulfuric acid and place a shiny iron nail in it. One observes only slight bubbling. The nail stays for days without visible changes. Contrasting experiment with half-concentrated sulfuric acid.

Ex49b Water–Free Formic Acid In a similar way, water-free (anhydrous) formic acid shows unreactivity with magnesium ribbon. The metal only becomes slightly shinier.

We can then say that acid, in the original sense, first arises when it comes to the reaction of a specific caustic material together with water. On the other hand we saw above that too much water can make acidity disappear again.


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We can propose the following series:

Sequence of Acids

One now finds acids (vinegar, formic acid, phosphoric acid) that are fairly caustic when water-free, anhydrous, but not ‘violent acids’ with the strength of concentrated hydrochloric etc.; they jump much more to the level of ‘strong acids’ with the addition of water. They cannot bring the indicator paper to the strongest possible color for ‘acidity’ (pH value-0) with small additions of water (e.g. concentration of 1M). Each specific acid has its own way to either intensify its acidity or to diminish it and develop it bit by bit. Quantitatively these differences are expressed in the amount of dissociation as well as the so-called activity coefficient of hydronium. The latter indicates in the conventional picture “that portion of the active within the totality of existing atoms, ions or molecules” (Rompps Chemical Dictionary).

The differences between the so-called strong and weak acids become especially evident as we transition from the mineral to the living (“organic”) milieu.

While hydrochloric acid openly displays its typically mineral acidity, so that each increment of dilution or neutralization is directly expressed also as a corresponding change in acidity and in pH value, vinegar shows a more closed, in certain respects


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“coiled” character. It also achieves in its most acid form a pH value of approx. pH=2.4, which rises slowly with dilution (see table).

For vinegar, we have:

Dilution pH

1 mol / L 2.4

0.1 2.86

0.01 3.4

0.001 3.86

However, when vinegar is neutralized stepwise with sodium hydroxide, the acid does not disappear as quickly as would be expected based on its strength (its pH-value), rather it persists longer. It virtually intercepts base addition; it can internally hide itself away. It is as if the acid from the beginning conceals itself, mobilizes its latent reserves, so that it then still requires the same amount of sodium hydroxide to ‘disappear’ at neutrality as hydrochloric acid with a similar molarity.

In that vinegar is partially transformed into its salt with base addition, it shows the so-called “buffer effect”. This name was borrowed from railroad technology, to characterize the damping effect of such an acid-salt solution against the full penetration of added acid or base. The buffer capacity is greatest when the acid and salt exist in solution in equally active chemical amounts; as if the acid first needs some base addition to be brought to unfolding its capacity to intercept (buffer).

It is important for the lesson to know that all juices and liquids in living organisms demonstrate such a buffer effect.


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E49b Buffering Of Egg white And Milk

Mix equal weights of raw egg-white and physiological table salt solution put into small container with either 10 ml 10 drops of universal indicator “Merck” ph 4-10. Unmixed physiological table salt solution serves for comparison. Now is added from a pipette, dropwise, dilute hydrochloric acid (approx 1 normal or more dilute). While one drop is sufficient to reach a red color (pH<4) in the physiological table salt solution, much more is required in the egg white solution to change the originally pale green and clear solution to red. If one repeats the experiment with milk that is diluted with distilled water in a 1:1 ratio, it is also demonstrated that the clear red indicator color requires addition of many drops of acid. In distilled water alone the indicator changes to red after 1 drop of acid.

Similar experiments with dilute sodium hydroxide instead of hydrochloric acid show equal buffer capacity of both the ‘organic’ liquids in the alkaline region.

This means that sharp peaks and extremes of acidity and alkalinity are avoided; that the mildly-polar milieu necessary for life is always maintained and defended. Especially blood shows in this respect a truly expert performance to not be displaced from its optimum pH of 7.38-7.42 by either acidic or basic metabolic products. Towards this end assist hemoglobin, carbonic acid with its salts and also phosphoric acid or phosphate. Only serious illness like for instance Morbus Cushing, diabetes or kidney deficiencies can diminish the blood’s buffer capacity.

IV-C The Picture of Acid and Base in Various Reactions

If one wants to go into more depth concerning the qualities of acidity and alkalinity, one can try to bring them into a more visual context with larger demonstration experiments.

Ex50 Formation In Mineralogical Process

Into saturated sodium sulfate or potassium chloride solution one adds concentrated sulfur—hydrochloric acid or alkali solution: interesting precipitate (less pronounced with table salt); floating with alkali solution. (concentration precipitation).


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Ex51 Formation In Plant Process (insofar as not already done in 7th Grade) Here various fruit juices or also the well known red cabbage juice can be decomposed by acids and bases (see appendix, indicators)

Ex52 Formation In Animal Substance The picture of acid and base in connection with how they affect milk: three medium size beakers Very characteristic images are found with egg white and egg yolk.

Ex53a Acid And Base And Their Effect On Each Other (inasfar as not already shown in the 7th Grade)

Fill an aquarium with water before class and illuminate it from the front, diagonally–because of air refraction. Pour in pressed red cabbage juice, followed by alternating acids and bases mixed with a shot of water: the colors and movement make clear the process of neutralization.

One can describe acids and bases generally, as already done in my text for the 7th Grade (p. 41-51 and p. 88 in my book “Chemistry Lessons for the 7th and 8th Grades”).

In the 7th Grade a lot remains in the background, which now in the 10th Grade is to be worked through with awakened judgment. To experience polarity the students can be given the assignment, for example, to bring examples of all things in the world that are in opposition to each other and also things that arise through resolution of opposites. The dissolved, spread out solution, and the pulled-together crystallized salt are for instance also such opposites, a degeneration of the acid and base ‘gesture’ that exists within the salt. So, outwardly, the salt has two different sides within it: the acid makes it light and soluble, the base promotes solidity and immobility.


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In all, one has the impression that acid and base move through nature as two non-material principles, which, when we reach for them, always show one-sided variations developed through their origin (acid from sulfuric, heavy; from nitric: changeable, decomposing)—as the individual acids and bases. The general nature of acid and base becomes a little bit clear when they are in their dilute form. Essentially they remain ideas, characterized by the gesture of flying upward and sinking downward through fire.

If one wants to make the problem of buffering more clearly understood, titrations lend themselves well for this whereby dropping in a strong base neutralizes various chemically pure acids including indicators. One must be aware, however, that such colorless and clear solutions of single acids and bases only exist in the laboratory and represent situations far removed from nature, while the actual buffer milieu rules in the buried fluid realm of living things.

Ex53b Titration of Various Acid Solutions

Dissolve 100g sodium hydroxide in 150 ml distilled water, and after cooling pour into a 50 ml burette–stopcock closed tightly! Into each of a series of 100 ml Erlenmeyer flasks, add 50 ml of the following dilute solutions of standard laboratory acids: 1% hydrochloric acid | 1% phosphoric acid | 1% formic acid (ant acid) | 2.5% citric acid or vinegar Taste all 4 solutions, and then add enough universal indicator (Merck pH 4-10) that a clearly red color develops. Now the base is added drop-wise from the burette to the row of acid solutions, at first quickly, later—as the red disappears—more slowly. After the yellow color has appeared, the drops are counted, until the indicator turns violet as in a basic solution.

One experiences here a clear polarity within both mineral acids and also within both non-mineral acids: While the color change in No. 1 and 3 was rapid, the color change in No. 2 and 4 played out over a larger number of drops and color stages. In the first case


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both the volatile acids barely develop a buffer milieu, while in the second case a strong buffer mixture is produced by the non-volatile acids.

IV-D Relation of Salts to their Daughter Products

In the time of one week we have gotten to know individual acids and bases, that can be obtained from salts. There is often a marked resemblance between the properties of the particular salt and the acid / base obtained from it. So, for example, the nitrates are all very water soluble; they melt at low temperatures and begin simultaneously to decompose. Their light yet stormy decomposition becomes a massive phenomenon in gunpowder and various explosives. This volatility extends itself to nitric acid. As an acid-gas it is not very stable, meaning on one hand easily decomposed—through oxygen release—and on the other hand easily regenerated through oxygen uptake. The special character of the nitrate finds itself again in a modified form in nitric acid.

Another group of salts, the carbonates, are in most cases susceptible to acids. The salts become totally decomposed and transform themselves with strong acids into foaming masses. Out of these salts one can obtain carbon dioxide. In solution with water, carbon dioxide has just as little presence as when combined in its salt, it produces little warming.

The alkaline earth and heavy metal carbonates demonstrate not only susceptibility to acids, they become especially easily and completely decomposed by heating. The residual material is porous, often barely water soluble, ash-like. The low stability of these salts serves to predict the earthy character of the corresponding highly insoluble bases that can be produced from them.

The salts that can produce such bases, as for example copper vitriol and also iron vitriol, have the special property to be weak acids in solution. Attempting to neutralize them with base, they gradually decompose and the base emerges. Attempting to de-acidify them through large dilution, they similarly decompose; the base becomes visible as slight haziness in the water (hydrolysis). These salts can evidently only become stable solutions at high concentration or with help of excess acid. They cannot be brought to spread apart widely in solution (be diluted) by physical motion. Also here is


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predicted the special nature of the bases obtainable from these types of salts—it is precisely those that that lean towards the earth-heavy state (high specific mass, slight solubility). Salts which have special stability with respect to heating, for instance the alkali chlorides and sulfates, with decomposition that is only possible through extreme methods, produce strong acidic gases with low volatility when in water, and reactive bases that are easily soluble in water. The stable salts, as for instance table salt, are precisely those that produce neither especially volatile acids nor especially earthy bases. [they are ‘balanced’ in the salt-base poliarity]

The acids and bases receive their special properties from their always necessarily special production, from this or that salt. The general acid-nature is in contrast as an answer to the universal fire reaction of salt decomposition—yes even also the normal wood burning, as we saw in the 9th Grade.

In reviewing not only this lesson concerning acids and bases, but also many others that appear in Chemistry, one notices, that the number of types of bases far overshadows the number of types of acids. Alkalinity is more fully differentiated as a substance in non-living nature than is acidity. There are only a few acids and these have very marked differences in, for instance, oxidation and reduction reactions or in volatility. Excepting for the pair: hydrochloric / hydrobromic, there are hardly such similar pairs of acids. It is completely different with the bases. The sodium-base is similar to not only the potassium-base, but also has similar properties as the lithium, barium, cesium and rubidium on the side (see footnote concerning nomenclature in appendix). And the similarities increase even more with the heavy metal oxides. Just as we also have more differentiation on the solid earth than in airy realms, so it appears that the group of bases is more split up into individual compounds than that of the acids. The acids that break off from special bases, like chromium, vanadium etc., themselves also become quasi influenced by the intensification of the base split-up.

From substances of living nature, we find in contrast a great majority of acids, and indeed in the realm of life acids rule.

Salts, Acids & Bases Chap. 5. Acid-Root / Base-Root

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Grade 10 Chemistry Manfred von Mackensen (1988) V-1 PRODUCTION OF SALTS FROM ACIDS AND BASES

Ex54 Artificial table salt (duration ca. 15 minutes)

After about 5 – 10 minutes, the chloride-gas which is produced out of the reaction of sulfuric acid and table salt, is made to pass over the soda-base (Na OH). Out of these reactants, along with production of heat, little branches and cauliflower-like crusts grow up. Thereby water vapor disappears, which soon begins to condense in the reaction tube. We can’t taste the watery condensate in the tube, since it has hydrochloric acid gas dissolved in it. IN any case, we should allow the salt-crust to be tasted, of course with precautionary measures. With imprecise carrying out of the experiment it can happen that under the dry salt crust, in the interior unreached solid particles of soda lye remain. This can occur due to the starting material reacting with carbonic acid (from CO2 in air) or allowing the reaction to proceed to briefly. Also, the lye pellets lying at the zone of gas inflow may not fully react due to insufficient self-heating (too much heat is conducted away). One will therefore carefully lift the salt crust out with a spatula.

1) Test, in a small portion, whether fine particles remain; 2) only allow careful tasting of a crumbly portion which was carefully removed


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V 1a. Formation of Neutral Salt Slurry

Ex55 Formation of Neutral Salt out of corrosive Acid & Base

Instead of the preceding experiment–somewhat tricky but impressive–we can react soday lye with hydrochloric acid. Drop in 10 pills of soda lye pellets into 4 mL of concentrated hydrochloric acid in a 250 mL high-form beaker; soon they begin to sizzle and hiss, a salt-slurry begins to sink down in the liquid. A portion is then boiled down, and we recognize from the pungent-smelling gas that we are still under acidic conditions [ventilate to remove the gas]; hold the beaker with tongs and heat to dryness, cool, and the dry salt powder may now be tasted. [Since H Cl is a gas when pure, it is possible to drive off the remaining excess acid reactant in this case, safely leaving the relatively pure salt product behind.]

In the salt that arises, the extremely aggressive soda base disappears without a trace just like the sharply corrosive gas (acid anhydride). And out of these two very dangerous, almost deadly substances (acid-gas and soda-base) arises edible table salt and water, which are even necessary for life.

How can the almost harmless water be formed out of both of these aggressive substances? Probably only because somehow previously, they were made by the violent transformation (splitting) of salt, the acid and alkali were produced [and through transformation by soda-ash, produced also by decomposition, with burnt lime (Ca O)–in any event coming from splitting.]. These artificial substances, poisonous to life eliminate themselves in their polarity. The capacity to form a salt, is plainly remained bound up with both of the salt-debris: acid and base. They ‘heal’ one another.


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Neither the unstable base, nor the volatile acid-gas are suited for such a ‘cool’ impression, as given by the crystals that arise (after evaporation and re-crystallization). If we sprinkle table salt all over a landscape or an interior, a cool, winter surrounding would emerge. Thin salt layer spread little by little upon black paper can provide such an impression. We can see how the ‘cool’ impression is connected (by polarity) to the intense heating whch accompanies salt-formation by neutralization. Also the fact that in salt, we have before us something solid, rigid, stands in an understandable relationship to the fact that in salt formation/neutralization, considerable amounts of outwardly mobile water vapor is developed and vanishes.

Mnemonic: all salts, which arise through neutralization by hydrochloric acid, are called “chlorides.”

V-b. Cupric-Earthy-base as Means of Neutralization Ex56 Cupric earth-base as a Means of Neutralization

Pour a known amount, for example 20 ml of concentrated sulfuric acid (36 g) onto ca. 15g of black vitriol ash (Cu 0). Adding 80 ml water, there is a sudden appearance of a blue color in the solution. Heat it up, decant the majority, cool, crystallization occurs (develop first with the decanted-residue).

Herewith we have reversed Ex24, we make the connection. At least by now each student should have made a Salt-table, e.g. the one that follows. With its help each one can individually discover which acids and bases can be made out of particular salts and further which salts through combinations of these. The students determine how many combinations we can make out of the acids and bases we have studied, and how these are named.


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V-2 Table of Naturally Occurring Salts

Common or Chemical or Mineralogical name Analytic name Formula Lithified salts (no taste)

Barite Barium sulfate Ba SO4 Fluorite Calcium diflouride Ca F2 Apatite Calcium hydroxy phosphate Ca5 (PO4)3(OH)

Semi-Lithified salts (only faint taste) ¶ Gypsum Calcium sulfate dihydrate Ca SO4 · 2H2O ¶ Calcite, Selenite, Limestone Calcium carbonate Ca CO3 Dolomite Calcium magnesium carbonate Ca Mg(CO3)2

Encrusting Salts (soapy & bitter) Thenardite (Glauber's salt) Sodium sulfate decahydrate Na2SO4 · 10 H2O Arcanite Potassium sulfate K2SO4

Aromatic/spicy Salts blanced char., salty taste, aromatic ¶ Table salt, Halite Sodium chloride Na Cl ¶ Sylvite, "diet salt" Potassium chloride K Cl Ammonium alum Ammonium chloride NH4 Cl

‘sal ammoniac’ Desert Salts

Potash Potassium carbonate K2 CO2 ¶ Soda ash (washing soda) Sodium carbonate Na2 CO3 · 10H2O “Trona” –source of sodium carbonate Chile Saltpeter Sodium nitrate Na NO3 ¶ Saltpeter Potassium nitrate K NO3 ¶ mason's saltpetre calcium nitrate Ca (NO3)2 · 6 H2O

or 'lime saltpeter' Argentite (phot. salts) Silver nitrate Ag NO2

or Lunar caustic Cerargyrite Silver chloride Ag Cl2

Bitter Salts ¶ Epsom salts Magnesium sulfate Mg SO4 · 7H2O Biscovite, magnesia chlor Magnesium chloride Mg2 Cl2 · 6H2O ice melter, halite™ brand Calcium chloride CaCl2 · 6 H2O

Corrosive Salts astringent, metallic ¶ Kalinite, Alum Potassium-aluminum sulfate KAl(SO2) · 12H2O ¶ Chalcanthite, blue vitriol Copper(II) sulfate CuSO4 · 5H2O iron stone, green vitriol Iron(II) sulfate FeSO4 · 7H2O - - Aluminum chloride Al Cl3


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But how can we directly grasp salt reactions for which no acids or bases are isolated in the process and afterward put together in another combination?

V-3 THE CONCEPT OF ACID-STEM AND BASE-STEM

Ex57 Determination of Chloride

a) Repeating E34, drip concentrated silver nitrate solution in dilute hydrochloric acid: white, cheesy precipitate.

b) We produce the same results, if instead of hydrochloric acid we use a table salt solution as produced in E54 or 55; or copper chloride, magnesium chloride, etc. All precipitates darken in the light—everything produces silver chloride.

Ex58 Volatilization Of Silver Chloride

Pour concentrated sulfuric acid over the silver chloride obtained in the previous experiment in a test tube. (One should have at least a pea-sized mound of cheesy residue, washed once.) Often already before heating we can establish the smell of the hydrochloric cloud; it is even free of sulfuric acid.

Ex59 Qualitative Assessment Of Acid-Parts In Taste One allows the students to come up one at a time and taste the different taste-directions that develop from chloride and sulfate—in the following order:

Sodium chloride, Na-sulfate

Potassium chloride, K-sulfate Magnesium chloride, Mg-sulfate

When acid and base come together, so again salt is produced anew. We do not say: the salt is composed of acid and base. Rather: it can re-emerge from both of these. Salt does not have acid and base within itself, rather acid and base can have salt as a beginning and as an end. In this chemistry block, which leads from the whole into the parts, we will not yet derive salt as merely the product of reacting acid and base. For, one can certainly make it from these, but not fully understand it. For instance, by what do we characterize nitric acid? Surely, it is largely through nitrate-stem, and how it


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appears in reactions. By another aspect (but not yet at this grade level) through the elemental chemistry of nitrogen, oxygen, and particular element-combinations; that comes in the 11th Grade. If one were to now consider nitrate by itself, independent from nitric acid, the concept of it would remain outside and poorly penetrated. It would then be a purely factual concept, akin to a long list of physio-chemical properties of nitric acid. We should strive much more towards a concept out of the varied appearances of all nitrates. No single substance satisfies this concept. Nitric acid is only a special variation, another is nitroglycerin, another calcium saltpeter etc. Especially with the strong acids and caustic bases–which don’t arise like carbon dioxide from another side entirely, namely from simple combustion (of wood), and which cannot yet be diverted towards the elements we will soon study, we will start with salt—which means leading thinking from the whole into the parts.

The last experiments are intended to develop a new concept, that reflects the above way of thinking. We are dealing with the so-called acid-root / base-root (-stem or -residue). In order to base the development of these concepts entirely on the phenomenon, the well-known, habitual ways of thinking must be left behind, and perceptions must be interpreted in a new way. With the word acid-residue, we usually imagine at least a compositional model if not an ionic model. In contrast to this, here we shall try to understand acid- and base-residues purely phenomenologically, without mechanical models.

If we want to totally dispense with the overall-concept of acid- and base- residues (-root) the we have aspired to here, and remain with what has been discussed up to this point, we would have created a rich and also well-connected picture of the outer appearance of salt, acid and base: however, the inner chemically based explanations of the subject would remain obscured. They would even in this case be constantly used by the teacher, but remain un-stated. This would be unsatisfying for the student; they would only get these concepts later and then presented in model-based concepts, expressed through formulas. They are easy to learn as formula concepts, but become falsely understood as an outer thing (e.g. as the SO4

-2 ion). [rather than a process.]

Throughout we have observed how salt formation maintains itself as a possible outcome of the daughter products arising (Ex54-56). Now we can turn the question around—for instance the identification reaction Ex54 leads us to this—whether the


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daughter products quietly announce themselves in the whole salt or strongly contribute to its behavior. Is the ‘splitting’ already predicted as a double nature in the salts?

Among the salts, the chlorides are characterized through their taste and crystalline form as very loose and changeable (e.g. expression of cubic form in alkali salts). In a chemical sense we understand—based on our experiments—under chlorides a salt, out of which (possibly through detours) acids can be made and that themselves can be made through use of acids. This is shown in the schema for our reaction:

Chloride-acid (hydrochloric acid) soda-base

silver nitrate Sodium Chloride Water vapor

sulfuric acid silver chloride sodium nitrate

silver chloride-acid (hydrochloric acid) sulphate

In the undisturbed salt, the so-called chloride is never encountered as an acid and certainly not as the component ‘chloride’! And nevertheless we get the typical hydrochloric acid reaction for silver chloride precipitation also with table salt etc. The same amount of silver chloride is even produced when we add the same amount of hydrochloric acid directly to sliver chloride as we would have needed for the reaction with table salt. The sodium nitrate solution remaining after complete precipitation from table salt is the product of the hydrochloric acid reaction: neither occurs further precipitation of silver chloride, nor can the hydrochloric acid be removed by purification or displacement by sulfuric acid. The latter was however successful with the produced silver chloride. The potential for hydrochloric acid production has moved into the silver chloride. If this were totally decomposed, then the hydrochloric acid used in the beginning (for the formation of table salt) would come back in exactly the same quantity.


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The possibility (potential) for silver chloride precipitation and for the appearance of hydrochloric acid is present, then, in the chloride and is passed along in reactions with the material changes, eg quantitatively, without the intermediate appearance of hydrochloric acid.

For, the entire acid is not passed along, rather only its characteristic nature which metamorphoses acidity in it’s characteristic manner, which we call hydrochloric acid. If we add general acid nature (acidity) to our experiment with sulfuric acid, then out of chloride becomes again hydrochloric acid. Truly observable then is a past and a possible but reliable future which always presents itself when particular inner natures come together (acidity and chloride). The reactions of these inner natures can be summarized through the concept of a theoretically ideal acid-root (-part) connected with the chlorides and the hydrochloric acid.

The acid-root chloride is never obtainable as a pure substance. It has no chemical forms that can be traced back to a single acid-part. The latter is just a modification of the respective base (of the base-root, see below). Yes, even in the pure acid, the acid-root shows itself only as a particular modification of generally ‘being acid’. Being acid by itself does not give a chloride reaction (as its absence with sulfuric acid proves). Hydrochloric acid (Salt-acid) would then be ‘chloride acid’.

Chloride should not be thought of as a material component, but rather as a causal quality. We grasp it as a related concept of reaction types; but also of properties such as taste direction and color (the latter more with base-parts). Chloride is therefore not the name of a substance, rather of a process: a way to modify other things (acidity, the bases). It is the concept of something that activates reactions, has never dwindling transformational power, that always appears in the production of other substances, and that variably modifies through others. It has similarity with matter inasfar as this variable or quality acts within the framework of particular masses, e.g. never dissolves into nothing. So arises the attempt to understand it as material components, from which the described effects originate. The components thought to be the underlying basis are however theoretical. Erroneously one transfers them forward and then thinks they are the primary reality. Through this one cuts oneself off from entering the observation.


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One considers them only from the point of view of theoretically determinable signals from particles. And one thinks in physical, actually mechanical categories because we do not search for chemical ones. Our problem reduces itself to the question, what one is actually searching for. Atomism does not act as a statement of being, rather as a first line to block the search.

The next experiments will show us that from individual bases extend a similar kind of modification of appearances that promotes itself through all other transformations. We can ground a formalism or rationale based on this experience of the self-promotion of bases—as the acid specialties: every acid-root (part) and base-root brings a solid, unique quality into existence. And every salt is a modification of two such qualities on each other. We can hereby formulate the salt as a combination of these two parts. For example there is the base-part Cupric and the acid-part sulfate. The salt formed by modification of the two on each other is rightfully named cupric sulfate. Because all the parts promote themselves, one can easily write reaction schemes (equations?) and with their help even predict unknown reactions.

The ever branching reaction schemes remind us already outwardly of the picture of a family tree. This similarity in shape even addresses an inner truth: a person assumes certain family inherited characteristics from their parents, but develops them always individually (this comparison is naturally also suspiciously anthropomorphic). For possible further investigations on the theme Roots (parts) we regard the following schemata. Exact experimental descriptions have been omitted.


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Sulfate-acid cupri-base

(sulfuric acid)

cupric sulfate calcium chloride

(vitriol)

cupric chloride calcium sulfate

(gypsum)

lime base sulfate-acid

After a few days, when the students can manage the concept of parts, one can, for better perspective, abbreviate the acid-part with S (A) and the base-part with B; the following is the shorthand version of our previous reaction equations:

B1b + A1a à B1A1

B1A1 + B2A2 à B1A2 + B2A1

B2A1 à B2b + A1a

a = the acid-like b = the base-like

A1 = sulphate B1 = cupric base-part

A1a = sulphate acid B2 = lime base-part

A2 = chloride B1b = cupric base

B2b = lime base


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The abbreviated version presents the logical structure of the entire subject area of salts, acids and bases to an organizing perspective. The thoughts as such become evident in it. This is more than an imitating involvement in the structure. If this rationale had even been nominally introduced in the beginning, it could have gradually contributed to the mastery of the qualitative aspects of the Roots within the logical structure.

Despite everything, there may remain an uncertainty within the students: what are the Roots really: qualities or just potentials—quantitative pieces of matter or generative transformational forces? The lesson merges here on a philosophical question of identity. And particularly with central, subject based material relationships, not with garnered supplemental themes. This reality, and not the textbook ready answer, exemplifies a true high school lesson. It encourages the awakening judgment to push forward into the unknown, leaving out what is still undefined. Each student is individually compelled to take a stand. It may also be discussed whether the ubiquitously named “Part” is accurate. One evokes with this namely the characteristic of being left over, a material residual, which however never exists. In this respect threatens confusion between a cupric ‘part’ and the copper ash left over after purification of sulfate. One recognizes with the help of formalism that within the great variety of salts there operate only a limited number of fundamental qualities (Roots). The universal combinability of the paired qualities becomes evident and realizable. They metamorphose themselves from salt to salt. Also between the most extreme representatives there are means of connection (step-wise exchange between Roots), so that between all salts there are relationships. To practice this viewpoint of salts according to acid- and base-roots one can delineate the Roots in the Schemata with different colors.

After one has followed the acid-root chloride (and eventually also sulfate) as representative of all other experimental results and has made them a foundation for the acid-root concept, the base-parts would now be in line for corresponding conceptualization. One could proceed here purely conceptually, supported by previous experiments such as those with copper salts.

Instead of a diagnostic reaction, the presence of a certain quality expressed by the cupric base-part lets itself be observed in the green-blue to blue-violet color tones of this salt. Base-roots that do not make such a characteristically colored solution, have instead other special properties such as the flame color of the sodium-root.


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Differences between the qualities of the individual base-roots can be brought to life for the students through a taste test: one starts the set for instance with sodium and potassium chloride; magnesium chloride follows; then finally cupric and ferric chloride (the latter placed near a mouthwash facility).

The students know enough now to understand the core-problem in the Leblanc soda process2 (displacement of strong by weak acids). The calcining of soda can be shown easily in an experiment: the filtrate of a slurry of calcium hydroxide in soda solution no longer fizzes with hydrochloric acid (instead now the lime), it can become a strongly alkaline solution when evaporated.

When we begin with the students in the 10th grade to emphasize the recognition of, or at least witness of, the deeper identity questions associated with the Roots, this does not remain our only goal. Equally necessary is the exposure to technical processes and a sure mastery of detailed facts along with their application to fixed concepts. Examples of student’s written practice answers are included in the appendix. These are incomplete and un-evaluated suggestions.

2 An extensive depiction of the discovery and biography of Nicolas Leblanc and his discovery of the Leblanc process in 1791 can be found by Greiling: Chemie erobert die Welt (Chemistry Conquers the World); Econ-Verlag Dusseldorf. 1950.

V-4 ELECTROLYSIS

The opportunity presents itself at this point in the Unit to demonstrate in an easy way the electrolysis of salt solutions and to connect this with the Root-concept. However, one will have to omit much of this in favor of Part 4 of this unit (Physiological Observations).

The concept of acid-like (Saurehaften) and base-like (Basehaften) is sufficient for understanding these types of non-materialistic qualities. The individual acid- and base-


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roots, however, guide this manner of conceptualization deeper into the observations themselves, but bring too many inorganic details into the lesson material so that the Roots can rarely be fully developed and appear briefly or in single examples. So also will have to go the way of electrolysis, as intriguing as it may be for students. It should namely not come to pass that from the work done to develop the concepts of salt and acid one only sinks downward into the sub-sensible world of electricity instead of moving upward into the world of the living.

Ex60 ELECTROLYSIS OF SODIUM SULFATE SOLUTION

Instead of the ubiquitous Hoffman Apparatus for decomposition of water, we can use in the 10th grade the following open, large scale system:

The trough can be made out of glass plates sealed together with silicone; ca 50 cm long, 10 cm high x 4 cm wide, glass ca. 3 mm thick. The two platinum electrodes should in all cases have a 1 to 2 cm2 surface. They should not have a surrounding glass enclosure, as most of those provided by educational equipment suppliers are designed. They are mounted using a well insulated crocodile clamp and the lead wires firmly fastened to the table with weights. The electrodes are placed diagonally into the solution and the platinum strips ‘float’.

The medium-sized power supply is available in many Radio or Hobby electronics store; producing at minimum 3 amps, ca. 800 Volts from 110 AC (e.g. Siemens Type E 2512, price 11.50 DM). Fasten the leader cable to a small board with insulated wire staples and on the other side 2 banana plug leads (1 m long). In the middle stands the DC power supply, upright (to facilitate air cooling), only supported by the mounting board. The investigation is so arranged that one can bring it out, along with the simple accessories, and a separate power supply.


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WARNING: The entire setup, is unavoidably open and visible, and is not safe to touch! It can only be used by the teacher, and must be completely built ahead of time before it can be plugged in. Certainly the power plug is easily pulled first. Under no circumstances can any solution in the trough or flowing out of it be touched when the electricity is on (under voltage tension). Never leave the equipment unattended when turned on; and after the demonstration, unplug and supervise! These voltages are dangerous!

A) Initially we demonstrate the conductivity of the salt solution, and how the apparatus works: a) There is no current, e.g. the lamp remains dark, when the electrodes are placed in

the empty, air-filled trough. b) There is also no current when the electrodes are placed on a (possibly large)

table salt crystal or a Glaubers salt crystal (Na2SO4. 10H20), either inside or outside the trough–in contrast to a piece of metal.

c) One fills the container with ca. 2 liters de-mineralized water until 1/2 cm below the rim. The lamp remains dark (with tap water, weak gas development at the electrodes).

d) Now we put some red cabbage juice or universal indicator solution pH 1-10 in the water and sprinkle 40g (45 mL ~1 tsp) finely powdered Glaubers salt (Na2SO4. 10H20 F.W 322.19, = 0.06 M, 2% wt.) over the entire trough and gently stir (with a plastic spoon):

-fine bubbles develop on the electrodes and rise up; -the lamp gradually lights up

B. One removes the lamp from the circuit (which must be closed at this location), adds then the rest of the sodium sulfate, stirs and observes the growing evolution of gas and the color differentiation. When the salt is mostly dissolved, one can demonstrate the electrical relationships in the trough. For this one replaces the used lamp (bakelite base; well insulated and dry leads out of stiff heavy duty wire, ca. 40 cm long, with banana plugs, no slit):


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The ones by the plug will be immersed into the solution with a constant distance between them (ca. one hand width) and dragged through the entire trough; a supplemental variation of this distance would complicate the picture. We see that the lamp goes on everywhere.

A. Now we will prepare chemical investigations. First we will capture the gases evolved and identify it in the usual way (popping gas test for H; glowing splint re-kindles for O).

Already by the type of bubbles evolved one can tell that different gases are being evolved at the different electrodes. +) To conclude one can (after pulling the plug!) feel the warmth generated by the solution from the outside.

+) The much more strongly evolving hydrogen gas can with danger be electrically discharged above the electrodes with a match. The oxygen can only be captured by using a platinum electrode; on carbon electrodes it is changed into CO2.


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The electrolysis investigation shows that salt solutions (as well as acids and bases) counteract the presence of a voltage difference when exposed to this voltage differences through submersed electrodes. There appear a chain reaction of effects (called ‘current’), which gradually use up the voltage source. (Besides which the voltage of the source decreases immediately by an amount corresponding to the resistance of the source). This effect of the salt solution however does not pass through it without a trace – in contrast to pure metallic conductors: as everywhere in Chemistry the appearance of whichever effect always occurs at the cost of substances, which disappear in the process. Here it is the salt, whose concentration decreases. Thereby appear acid and base at opposite electrodes in corresponding concentration. The salt is broken down as through combustion—with electrolysis however it is in solution and much more quietly. The salts are evidently easily ready to develop themselves toward the acid and base polarities. The fact that the lamp lights up when immersing the lead wires into the solution shows that there is ‘electricity’ in the whole solution. There exists then in each part of the solution—even in short distances—a voltage difference between right and left sides. Everywhere one can ‘capture energy’.

If we focus our attention on the quantitative relationships alone, we can then build a concept of ions. It can be established that the amount of acid appearing at the anode is exactly the same amount of acid that one could have produced from the disappearing salt using other methods. If one considers then that salt is built up out of the substance components anion and cation, so comes about the concept concerning their movements and separation. Insofar as one understands the effects only in physical-quantitative and chemical-analytic ways (production model, particle model, loading model) one can explain everything, and apply it, with help of ion movement and the electrode reactions. The phenomenological approach may not even compete with this.

It goes in a very different direction, in that it asks different questions e.g. what is the significance of the emergence of opposition, of polarity? The effects of electrolysis are phenomenologically difficult to see through because of course electricity occurs in the varied ‘related’ phenomena of light, warmth, mechanical energy and chemical activity and does not have a self defining characteristic. Nevertheless our investigation shows how basic electricity is active: it always appears in the opposition of plus and minus, in a splitting open. If the splitting is waylaid, e.g. plus and minus metallically combined, so emerge only temporary warmth effects, and the original electrical effects have


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disappeared. Electricity then does not appear in the polarity, rather only in the splitting apart, because one cannot recognize from which unity this splitting originated. If we use salt solutions to act in opposition to electrical voltages, e.g. they are ‘flowed through’ by current, then the splitting apart of the electricity moves into and through the salt solution and opposing reaction products (acid and base) appear.

With splitting by fire, which appears in a totally different polarity (up and down, light and heaviness instead of plus and minus) the reaction products take a meaningful place in the whole of nature, oriented between light and heaviness: the acid-gases rise upward, the bases fall downward. The entire phenomenon remains included within the spatial order of nature. (see my “Chemistry Lesson for the 7th grade”). Electrical phenomena do not show such apparent ordering in a surrounding field. Furthermore one must take note in electrolysis where one has placed the plus and minus for the voltage source. The rule is valid: at the minus-pole (cathode) forms the base, at the anode the acid. The special action of electricity, to bring about opposition, can be further followed through in the electrolysis investigation to the determination of hydrogen and oxygen as the big opposing pairs of reduction and oxidation.

While in fire, acid-gas and base arise from the same salt kernel and from there go their own way, in electrolysis acid and base arise in spatially separated places (the electrodes). Somehow, at these locations, the unique properties of acidity and/or alkalinity must arrive out of nothing. Available is only the Root—it can migrate closer insofar as the solution volume, where the root of potassium permanganate, for instance, creates a color, edges toward the anode in the course of electrolysis (moving boundary layer). The acid quality as such must be obtained from the water at the electrode. And not in such a way that simultaneously the base arises as well, but rather acidity in itself. In the process the water is simultaneously polarized, meaning basically broken up, and a type of tremor goes into the environment—oxygen escapes. At the cathode it then has to be the hydrogen. These redox reactions at the electrodes must strictly be seen in connection with the redox reactions of ‘lead battery’ as current source. At the wire, on which in electrolysis something is oxidized (oxygen formation), something will be reduced in the operation of a battery (lead oxide becomes lead sulfate).

It could appear as if the sodium and sulfate roots were separated out of the neutral sodium sulfate through electrolysis and made singly available. In fact one can take


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colored Roots like permanganate etc. and see them migrate a as boundary layer in layered salt solutions:

Nevertheless, pure sodium never emerges. For it can only move to the cathode, when hydrogen is at the same time freed there. With that, water is lent the basic-character: sodium falls into being a base. Acid and Base characteristics do not arise here in the same place as with fire, rather they are separated to different locations through the electrical circuit. That is why – with water having to deliver both—hydrogen serves as “acid replacement” at the cathode and oxygen serves as ‘base replacement’ at the anode.

The degree to which salt solutions split apart under the influence of electricity is documented by their conductivity. It is—except for a small correction—put together totally additively from the conductivity rates of the parts. In the particle view these are single ion conductivities. Staying however with the phenomenon, one has only the fact that the conductivity of the salts combines two summands, which accompany the Roots and for all other salts are equally big. The ions themselves remain concepts, not phenomena.

V-5 THE INNER OPENNESS OF SALTS

The considerations of the last days let themselves be bought into the following scheme of reaction pathways:

From this one can work out the concept that a salt owns little of its own nature. It can be understood as the simple metamorphosis of an acid-part by a base-part and


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simultaneously of a base-part by the acid-part. The contrasting understanding, that salt is only an addition (mechanical imagined bonding) of acid- and base-root, leads to craziness. One can only add something that exists as an independent entity outside the addition. This is not the case with the Roots, they arise only as a metamorphosis by something else (by the salt-like, by he acid-like, by the base-like).

In the formula Salt = B—A

The A does not only mean that a previously defined quality (the acid-root) will exist similarly in the combination as it has been determined outside the combination, but also that this quality characterized already through many-sided other appearances of acids and salts, comes out in the given salt still in a new variation not defined by generalities. Each variation contributes to the total picture. The formalism alone can never replace the concrete phenomenon. If one holds oneself open in this way to the actual phenomenon, one can achieve a wide reaching order through the combination model of salts that is provided through the Roots. One can explain in a logical framework all possible reactions of salts, acids, and bases. From the theoretical possibilities, the most probable reaction pathway (a certain precipitation) can be predicted if one knows into which acids and bases the slightly soluble salts decompose. (Meaning which acid- and base-part concentrate themselves in low solubility).

There is now the opportunity to turn around the lesson direction in that one first works on the theory and afterwards shows the experiments that fall under it. The students then experience what R. Steiner recommended in the 10th grade for the Physics lessonplan—that in the face of phenomena (not just abstract personal space), strong and newly confident thinking can work out certain aspects of the appearances ahead of time. When we, for instance, dissolve two completely unrelated salts together, the acid- and base-parts can simultaneously recombine. We write the two reactant salts B1A1 + B2A2 in the following rearrangement amongst themselves:


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A shorter version produces the following simple formula: B1A1 + B2A2 à B1A2 + B2A1

Many reactions that we have done in the Unit fall under this formulation , e.g. Exp 26a, 57b, 62, 63.

When individual bases/lye solutions or acids/acid gases take part in this type of reaction, they are identified with a lower case a / b so that the following scheme is developed:

Examples were presented in Experiments 35, 36, 47, 48, 58

Thereby is produced: b + a = water, as in Experiments 26, 53, 54, 55, 56.

The openness of salts coming into expression through such playing with formulas can be made more vivid with a few experiments.

Ex61 INDEPENDENT SATURATION

One prepares separately saturated solutions of potassium saltpeter (45g + 100 ml water) and table salt (50g + 100 ml water), where 1/3 the indicted amounts remain solid (un-dissolved). Both the solutions, with their solids, are poured together. The two solids layer themselves over one another. Following short stirring, they almost totally dissolve.


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Ex62 RECIPROCAL SALT PAIRS (duration ca. 25 minutes)

Add 105 g sodium saltpeter (NaNO3) and 30 g sylvan (KCl) to 90-100 ml water, then heat together. Add boiling stones and heat further in a large container (250 beaker) ca. 20 minutes, in order to evaporate at least 70%. In the meanwhile one allows small amounts of each salt to be tasted. During evaporation a grainy deposit soon begins to develop, starting at the surface. It is table salt, whose solubility is being ‘undercut’.

We suction off the hot liquid and allow tasting of the table salt. To the filtrate, one adds at most 10% water to keep the remaining table salt in solution; as it cools, saltpeter (KNO3) precipitates out after a while (sometimes longer). After strong suction, the latter is also tasted. The tastes of the two reactant salts have polarized themselves in the two produced salts: out of weak bitter NaNO3 and sharply salty KCl come on one hand harmoniously tasting table salt and on the other the more bitter, horrible KNO3. In the technical process, the so-called ‘conversion’ of the hygroscopic Chile saltpeter, not usable for gunpowder, into the more useful—also as fertilizer—potassium saltpeter, one returns the reactant salts to the heated ‘mother solution’, after removing the crystallized potassium saltpeter, and resumes another round of concentration. In the potassium salt mines the potassium is also separated from the stone salt through hot solubilization with saturated table salt solution.

Ex63 A Second Reciprocal Salt Pair

As a repetition or variation of the previous experiment one can spoon table salt into a boiling, fairly concentrated solution of bitter salt (ca 60 g MgSO4 • 7H2O + 100 g water); in all about half as much table salt as bitter salt. After a few spoonfuls the cooking salt still dissolves, but the solution becomes gradually hazy and a finely flaky precipitate–in contrast to table salt—floats to the bottom: Na2SO4, Thenardit. It can be tasted after sucking off the liquid: alkaline sodium sulfate taste, overlain with better taste of intermingled magnesium salts. The warmth on the tongue divulges the anhydrous property of sodium sulfate. The solution enriches itself with the extremely soluble Bishovite, MgCl2 • 6H2O, it can be experienced as a sharply bitter test.


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In subsequent explanations of Ex62 one needs the temperature dependence of the saturation point for all four salts that can form from the acid- and base-parts utilized:

Table: Solubility, (in grams / 100 g water)

Temperature KNO3 NaNO3 NaCl KCl

0 ºC 13.3 73.0 35.6 28.5

20 ºC 31.5 88.0 35.8 34.7

40 ºC 64.6 102.0 36.3 39.9

60 ºC 108.0 122.0 37.1 45.5

80 ºC 166.5 148.0 38.0 51.4

100 ºC 246.0 180.0 39.1 56.6

If one would make a mixed solution, as in Ex61, but with low concentration so that all the salts are under-saturated, then the salts would all intermingle without any reactions. A mixed (under-saturated) solution of table salt and potassium saltpeter is no different than a solution made with sylvan and sodium saltpeter. If one has in both cases the correct mass relations (here enter mole-mass considerations, which come first in the 11th grade), then both these mixed salt solutions have the same mass, the same density, the same refraction index, the same surface tension, the same boiling point elevation and freezing point depression etc.

These concrete relationships lead us to the idea that the salts in their solutions are not only open to the surroundings in their outer appearance (see beginning chapter), but also ‘open’ at least to each other in their actual chemistry: acid- and base-root are ready to appear on their own and transform each other and determine as independently acting qualities the properties of the solution.

It is therefore not possible and even pointless to present the individual salts for a mixed salt solution as one put them in. The salts have totally disappeared in dissolving and active in the solution are only and solely the Roots (parts). A type of transition between a mixed salt solution and one of a single salt is made in ocean water. Table salt: that means a particular acid- and a particular base-root dominate quantitatively. One could


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produce more hydrochloric acid and sodium hydroxide from ocean water than other acids and bases. So one can speak of ocean water practically as a table salt solution. But a list of all contained salts is one-sided. One can only present the individual parts (this happens today in the terms of ionic theory). Which salts appear individually depends on the temperature and outer conditions. First when one exceeds salt solubilities at particular temperatures can one talk of complete salts. There is no clear salt content of the solution (nevertheless for ocean water an evaporation series according to temperature can be given, see appendix). The cause for the appearance of particular salts does not lie within the solution, rather in the outer relationships of the surroundings. Also here we find again the special relation of salts to the environment.

If one still has time available, one can examine the salts of sweet waters: water hardness. Here shows itself again the free combinability of the parts, when the temporary hardness is eliminated by heating and earth alkaline, not alkali carbonates, precipitate out.

V-6 QUESTIONS OF NOMENCLATURE

In the naming of salts is expressed that they do not have individual properties, rather are “composed” of twofold general qualities. Such names are for instance sodium sulfate, potassium carbonate, sodium chloride, magnesium sulfate, sodium thiosulfate. The common, historical names sound differently; with our examples: Glaubers salt, potash, cook salt, ‘bitter’ (Epsom) salts, fixer salt. These names do not reflect their logical structure in chemical processes (base-root combined with acid-root), rather their names are based on the following types of relationships: name of the discoverer (Glauber); origin, for instance in lye solution that was evaporated in large pots (potash); similarly with cook salt, that was produced by evaporation of brine; in ‘bitter’ salt a quality (bitter taste); in fixer salt to fix the development of light sensitive photographs. From the origin one can distinguish between the production process and the place of origin. The name potash refers to the production process, the name saltpeter to the mining origin.

The scientific names of salts already for the last 50 years no longer reflect the level of acid- or base-root at the stage of salt reactions. A name at such a level is for instance


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potassium carbonate (Kali-carbonate): potassium as base-part, carbonate as acid-part. In the systematics one has proceeded to basing the nomenclature on the ultimate products that can appear as elements after further decomposition of the salt beyond the formation of acid and base (e.g. chlor-sodium instead of sodium-chloride). In the case of the heavy metal salts, this type of nomenclature is more closely suited to the actual relationships, for here the elemental metals let themselves be produced from the bases with relative ease and with visible methods. If one focuses more closely on the properties of a given family of substances, in that one takes into account the fundamentally different color quality of the many copper salts in contrast to the red-brown color display of the metal, one will still prefer the designation “cupric” for the copper base-part. With the name ‘cupric’ the copper base-part is elevated to the level of an independent causal agent within chemistry. With the name “copper…” the unique effect of the base-part is immediately related to a type of substantive model, based primarily on a theoretical cause tied to the element copper, outside of acid/base chemistry. The root is misplaced for the phenomenological point of view. The older naming system is also more aligned with the phenomenon in that it expresses with cupric and cuprous the different oxidation states. The latter can then be more easily understood qualitatively, in contrast to the more quantitative delineation in today’s naming system with oxidation numbers; earlier cuprous chloride, today copper (I) chloride. In the later grades, one must increasingly supplement today’s more widely used, poorer naming system with this older, no longer utilized one or–as decided by the teacher–even prefer it from the very beginning. The nomenclature used in the present text cannot generally be changed, rather only characterized in its problematics.


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V-7 THE DRIVING FORCE OF CHEMICAL REACTIONS

In all this it is also clarifying for the students to consider when chemical changes actually arise, and whether one can imagine anything like a driving force for a reaction. These problems are briefly summarized in the following table:

Crystallization: - Solution concentration through evaporation and/or

- Release of sensible warmth through introduction of cold

Salt Decomposition: - Heat

- Electricity

- Acid displacement, the less volatile acid is driven out

- Base displacement, the less soluble base precipitates

Neutralization: - Polarities are balanced

Deposition: - The least soluble root-combinations precipitate

Combustion: - The inflammable and burnable balance out (see 9th Grade)

Salts, Acids & Bases Chap. 6. Chemistry of Animal Juices

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Grade 10 Chemistry Manfred von Mackensen (1988) VI CHEMISTRY OF ANIMAL JUICES

VI-1. INTRODUCTION

A fourth aspect of this block is to go further into physiological phenomena, and acidic and basic processes in the animal kingdom. Steiner describes it this way in his teaching indications ("after [introducing acidic and alkaline] connect to the physiological processes so that [the students] acquire an understanding of them."). However, I am not aware of any practical teaching-outlines for this topic, which stand up to scrutiny [as of this edition, 1988]. People are groping in the dark. Admittedly, it would be easy to describe all sorts of juices and tissue fluids from various animal and human sources, and have the students learn the composition of each of them. But, this would either lead into natural history [Biology, rather than acid/base chemistry], or else towards a dubious materialism: treating the animal organism like a chemical mechanism. Plainly, it all depends on also developing the acidic and alkaline aspects of this kingdom of nature by means of experiments. For these experiments we must take the opportunity to approach the life-connections of these animals, so that the chemical phenomena do not remain isolated, and acidic/basic processes are raised to a physiological expression.

1.1 CONCERNING THE "BEE PROBLEM" IN THE CURRICULUM INDICATIONS

The whole bee hive is like a living being (the "bee"), in which the animal metabolic processes, which otherwise lie concealed in the dark inner spaces of an animal's body cavities, are brought to manifestation to such an extent that we can study them without dissection. In a way, metabolism takes place between the bees.

When a normal worker bee hatches 21 days after its egg was laid in a capped honeycomb cell, it serves as a "nurse" for the first 10 days of its 4 to 24 week life span. It labors within the hive, exclusively for the colony. Its most important tool is the royal jelly gland, which is situated on its head, which is developed to great size instead of saliva glands. With its help, the "nurse-bees" process the pollen supply of the hive into a protein-rich, nourishing secretion. With it, the 3-day old hatchling larvae are fed, one can even say "fattened." For, during the next 6 days, the weight of the larvae increase 500-fold – which would in a human baby correspond to a 1,600 kg nurseling! For this goal, the nurse bee must have produced sufficient royal jelly three times per hour for each of the many larvae in its care. In fact, the


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larva of a future queen must receive fresh royal jelly every 2-3 minutes. From this "Weisel-royal jelly" usually over 10 times more pantothenic acid1 may be isolated than for ordinary royal jelly juice. However, there is no difference in terms of acidic pH value, which year round remains around 4.0-4.2 pH. The development of the male bees, the drones, is dependent on an important time-factor: they require a whole third longer development time than the worker bees, namely 28 days. The queen, in contrast, is finished with her development from egg, larva, pupae and nymph, already in 16 days. Both of these latter two stages are completed in the enclosed space of the "capped" cell.

If the young bee has completed its "nurse" duties, then it becomes a "worker" bee. During this time which lasts around 10 days, beeswax is its tool and raw material. It builds new honeycomb cells, takes care for the hygiene of the hive, and does watch-duty at the door to the hive. Only then are they allowed to fly outside, and for 1-2 weeks bring in the nectar-fruits. Its royal jelly glands have metamorphosed in the meantime, and supplies the enzymes necessary for transforming the nectar: invertase, diastase and oxidase.

If we are talking about the blood of the bee, we must be clear that this isn't a red juice which flows through their body in some kind of circulatory system. The bee has only an open, tubular blood-system with a thickening in it, which could be described as a sort of heart. Within this system, pulses an almost colorless blood whose pH value lies very near the neutral point: 6.5 - 6.8. It is more "basic" than the royal jelly, but not actually alkaline! In comparison to distilled water it even appears weakly acidic. Further interesting points are contained in the well-known book "From the Life of the Bees" by Karl von Frisch, which has continuously appeared each decade in new editions.

The pH values cited here are from the Institute for Bee Science in Oberursel/Taunus (personal communication). Much can also be found the work of Bündel and Herold: "Bees and Bee research" (Munich 1960). Spiritual-Scientific findings about bees and their environment have been given by Rudolf Steiner in his lectures to the workers (Nov-Dec 1922; GA 351), especially lecture 10-Dec 1922 which discusses the connection between mouth-juices and circulatory-juices on the one hand and honey-formation on the other. The interplay of the ichneumon wasp with the sugar-process of figs is approached. This task, of attempting to survey together the indicated concrete phenomena into a characteristic

1 Note that pantothenic acid is the vitamin present in acetyl coenzyme-A, an important thio-ester that

participates in many physiological processes. Coenzyme-A can be considered structurally as a compound including pantothenic acid, a nucleotide (via a C-O bond to 3' 5'-diphosphate), and a nitrogen-sulfur residue (linked via an amide bond to 2-amino ethane thiol). [-translator: JP]


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concept of the acidic compared to the alkaline, that Steiner call upon us to pursue, should not be taken up here. It is unfortunately generally thought, that the inwardly enclosed blood, which forms the outwardly active 'royal-jelly' which is 'continued' in youthful life and finally in the swarming-out of the colony. Instead of a neutralization which seems obviously in the inorganic, we find a continual production of acidic and remaining-behind of the relatively basic. This plays a decisive role in its duality plainly for many of these kinds of organisms right up to the human being, as an outward-working acid, in contrast with a separating out (precipitating) base. Inorganic structures are one with the environment and are not bounded. Here it comes to neutralization. Only with an individualized living being (separated-out from surrounding nature) can we have the two sides of activity: towards outside and towards the interior: it must also have it and generate thereby the acid-base polarity.

From another side, one comes upon the acidic of the animal world also by means of [examining the properties of] formic acid. We can show especially well how this acid is flammable. In a beaker, mixed half and half with concentrated sulfuric acid, a flammable gas evolves for over 10 minutes (carbon monoxide), which at the end of a tube inserted, can be burned with a still, blue flame. The neutralization of formic acid with soda lye produces a salt that tastes almost the same as chloride salt (somewhat pungent-bitter, after moistening), which by ‘charring’ (heating until it smokes?) again produces a flammable gas. About the activity of formic acid in the forest soil we can find far-reaching indications in Steiner's ‘lectures to the Workmen’ and in my booklet “Formic acid, Oxalic acid, Uric acid.

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