ith General Science - Lekolar · 1 17729 Multi-purpose container (60.1) 2 47695 Syringes with tube coupling, 10 ml (64) 1 47636 Float (84) 1 47563 Suction flask with lid (85.1) 1

General Science

Experiment Description/Manual for the Science Kit

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work-

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Science Kit

General ScienceOrder no. 31500

This Science Kit is recommended for students at the age of 6–11.

Contents

List of components with illustrated packing diagrams .......................................4

I. Introduction .............................................................................................12

II. Air.............................................................................................................13

III. Balances and Equilibrium ........................................................................26

IV. Biology .....................................................................................................32

V. Chemistry .................................................................................................43

VI. Electrical Circuits ......................................................................................46

VII. Heat .........................................................................................................53

VIII. Light and Shadow ....................................................................................63

IX. Magnet and Compass ..............................................................................67

X. Sound and Tone .......................................................................................75

XI. Water Purification ....................................................................................84

XII. Wind and Weather ...................................................................................90

© 2009 Cornelsen Experimenta, Berlin All rights reserved.

The work and parts of it are protected by copyright. Every use for other than the legal cases requires the previous written agreement by Cornelsen Experimenta.Hint to §§ 46, 52a UrhG: Neither the work or parts of it are allowed to be scanned, put into a network or otherwise to be made publicly available without such an agreement. This includes intranets of schools or other educational institutions. The master copies are allowed to be copied only by teachers for their personal use in lessons with the required number of copies.

Cornelsen Experimenta products are designed for educational use only and are not intended for use in industrial, medical or commercial applications.

We assume no liability for damages which are caused by inappropriate usage of the equipment.

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List of components

Illustr. no. Qty. Description Topic Order no.

1 2 Flower press components ........................................................................ Biology 19225 2 1 Package of absorbent paper .................................................................... Biology 19012 3 1 Slotted stand as cardholder ......................................................................... Light 13707

4.1 1 Card showing human figures ....................................................................... Light 13766 4.2 1 Cardboard, square, smooth ......................................................................... Light 13758 4.3 1 Cardboard, square, rough ........................................................................... Light 13740 4.4 1 Metal foil ..................................................................................................... Light 13715 4.5 1 Metal mirror ................................................................................. Light, Weather 13839 4.6 1 Plastic plates, white, 90 x 90 mm ..........................................................Light, Air 13731 4.7 1 Synthetic pane ............................................................................................ Light 13723

5 1 Thermometer, without graduation ...............................................................Heat 12743 6 1 Thermometer, –3 °C to +103 °C ................................... Heat, Electricity, Weather 12735 7 1 Thermometer, –25 °C to +50 °C .................................................... Weather, Heat 13006 8 1 Screwdriver, insulated, 110 mm ........................................................... Electricity 13481 9 1 Pair of tweezers, stainless steel, 105 mm .................................................. Biology 17630 10 1 Pair of scissors, stainless steel, 115 mm .................................................... Biology 17648 11 1 Triple magnifier, 3x, 6x, 10x ..........................................................Biology, Water 17613

12.1 1 Test tube, plastic, 100 mm long ..................................................Magnet, Sound 12468 12.2 1 Bar magnet, without mark, 23 mm .........................................................Magnet 14967 12.3 1 Bar magnet, with red marked north pole, 23 mm ....................................Magnet 12450

13 1 Test tube, glass, heat resistant, approx. 160 mm ................................. Chemistry 19373 14 2 Test tubes, plastic, 152 mm ........................................................ Sound, Biology 17680 15 1 Test tube brush ........................................................................................ Biology 17699 16 1 Knitting needle, 210 mm.............................................................Sound, Magnet 12620 17 1 Stethoscope chest-piece ............................................................................Sound 19500 18 1 Set of musical bars for “Glockenspiel” .......................................................Sound 19470 19 2 Glass tubes, 220 x 6 mm ..............................................................................Heat 12859 20 1 Tuning fork (440 Hz) .................................................................................Sound 19446 21 1 Atomizer ................................................................................................Heat, Air 12999 22 1 Lever switch ......................................................................................... Electricity 13499 23 1 Test tube holder .................................................................................. Chemistry 19381 24 1 Knife, stainless steel ................................................................................. Biology 17656 25 1 Metal spoon ...............................................................................................Water 13197 26 1 Nail, iron, 80 mm ................................................................Electricity, Chemistry 13553 27 1 Dissecting needle, 140 mm ..................................................................... Biology 17621 28 1 Mallet, plastic ............................................................................................Sound 19489

29.0 1 Set of weights in plastic box, containing:................................................ Balance 15564 29.1 10 Weights, 0.1 g ......................................................................................... Balance 15645 29.2 10 Weights, plastic cubes, 1 g ...................................................................... Balance 15580 29.3 2 Weights, brass, 10 g ................................................................................ Balance 15572

30.0 1 Plastic box (no. 12662), containing: .......................................................Magnet 43142 30.1 2 Iron screws ..............................................................................................Magnet 12522 30.2 5 Paper clips ...............................................................................................Magnet 12549 30.3 5 Nails ........................................................................................................Magnet 12514 30.4 2 Aluminium rivets .....................................................................................Magnet 13626 30.5 1 Wooden disc ...........................................................................................Magnet 12590 30.6 1 Rubber eraser ..........................................................................................Magnet 12573 30.7 1 Sheet of copper .......................................................................................Magnet 12581

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Illustrated packing diagrams (top-layer)

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Illustrated packing diagrams (top-layer)

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List of components


30.8 1 Sheet of iron ........................................................................................Magnet 12611 30.9 1 Sheet of cardboard ..............................................................................Magnet 12603 30.10 1 Piece of cloth .......................................................................................Magnet 12557 30.11 1 Stone ...................................................................................................Magnet 12565 30.12 1 Sheet of brass ......................................................................................Magnet 43185

31 1 Connecting tube, transparent, 300 mm ..................................................Water 13200 32 4 Bulbholders ...................................................................................... Electricity 13448 33 1 Spool of thread, 100 m ............................................................Sound, Magnet 12485

34.0 1 Plastic box (no. 12662), containing: .................................. Electricity, Balance 13561 34.1 1 Copper ring ........................................................................ Electricity, Balance 13588 34.2 1 Rubber rod ......................................................................... Electricity, Balance 13600 34.3 1 Wooden disc ....................................................................... Electricity, Balance 12590 34.4 1 Brass screw ......................................................................... Electricity, Balance 13634 34.5 1 Aluminium rivet .................................................................. Electricity, Balance 13626 34.6 1 Glass bead .......................................................................... Electricity, Balance 13677 34.7 1 Piece of porcelain................................................................ Electricity, Balance 13650 34.8 1 Carbon rod ......................................................................... Electricity, Balance 13642 34.9 1 Iron nail .............................................................................. Electricity, Balance 13685 34.10 1 Piece of string ..................................................................... Electricity, Balance 13669 34.11 1 Stone .................................................................................. Electricity, Balance 12565

35 2 Tubes, 630 mm (stored between lid of the box and foam) ...............Sound, Air 19454 36 1 Flexible strip with oscillation head .........................................................Sound 19497 37 1 Plastic tube, transparent, 200 mm long .......................................................Air 47687 38 4 Ear-pieces for hearing tubes ...................................................................Sound 19462

39.1 2 Pegs, red ....................................................................................Heat, Balance 12751 39.2 1 Peg, blue ....................................................................................Heat, Balance 12778 39.3 1 Peg, yellow ..........................................................................................Balance 12760

40 1 Valve fork for propulsion vehicle ..................................................................Air 47865 41 2 Wooden beads .......................................................................................Sound 25101 42 1 Set of red stick-on dots ........................................................................Magnet 43274 43 2 Compass needles, 35 mm ....................................................................Magnet 12638 44 1 Floating platform for compass needle ..................................................Magnet 43207 45 4 Brass bearings for compass needle, 30 mm dia. ...................................Magnet 12646 46 2 Terminal clips .................................................................................... Electricity 13464 47 1 Spool of copper wire (20 m) with red plastic insulation..................... Electricity 13529 48 1 Spool of heating wire, with grey cotton insulation (20 m)................. Electricity 13545 49 1 Spool of copper wire (60 m) with transparent enamel insulation ...... Electricity 13537 50 2 Compass cards with pinhole 0.7 mm, black .........................................Magnet 2973 51 1 Compass with pointer lock, 45 mm dia. ................................Magnet, Weather 13057 52 2 Mini-waggons for bar magnets ............................................................Magnet 43282 53 1 Floating platform for bar magnet .........................................................Magnet 43215 54 1 Set of rubber bands (thin and wide) ......................................................Sound 19527/25071 55 1 Set of double dishes, plastic, 80 mm dia ..............................Biology, Air, Water 17710

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List of components


58 1 Insulating case for beaker (91) ......................................................................Heat 12808 59 1 Beaker, heat-resistant, 50 ml ....................................................... Chemistry, Heat 19365

60.0 1 Set of germination unit: ........................................................................ Biology 60.1 1 Multi-purpose container, 150 x 75 x 75 mm ... Biology, Air, Weather, Water, Heat 17729 60.2 1 Root-separator dividing plate ................................................................... Biology 18121 60.3 2 Germination-chamber inserts .................................................................. Biology 17737

61 1 Bowl with lid ...........................................................Water, Magnet, Sound, Heat 13111

62.1 1 Balance beam .......................................................................................... Balance 15483 62.2 1 Adjustment rider ..................................................................................... Balance 15491

63 1 Tilting mirror ............................................................................................... Light 13693 64 2 Syringes with tube coupling, 10 ml .................................................................Air 47695 65 1 Balance column ....................................................................................... Balance 15475 66 2 Scale pans with bow ................................................................................ Balance 15505 67 1 Dynamometer, 50 N/5000 g ................................................................... Balance 26922 68 2 Filter tubes .................................................................................................Water 13138 69 1 Spring scale, capacity approx. 25 g ......................................................... Balance 15548 70 1 Triangular bridge .......................................................................................Sound 19411 71 1 Seesaw beam .......................................................................................... Balance 15530 72 1 Spool of string with dog-bone ends ...........................................................Sound 25110 73 1 Rod on base for casting a shadow ............................................................... Light 13812 74 1 Seesaw bearing ....................................................................................... Balance 15521 75 2 Copper wire gauzes ....................................................................................Water 13146 76 1 Strainer for filter tube .................................................................................Water 13154 77 2 Push-on connectors for filter tubes .............................................................Water 13120 78 1 Electric torch with bulb................................................................................ Light 13775 79 1 Rain collector, with graduation, 83 x 36 mm ..........................................Weather 13014 80 2 Battery, round, 1.5 Volts .............................................................................. Light 39218 81 10 Bulbs, 3.5 Volts, 0.25 Ampere ............................................................... Electricity 13430 82 1 Battery, square, 4.5 Volts ...................................................................... Electricity 13359

83.0 1 Set of accessories for germination unit: ............................................... Biology 83.1 12 Special absorbing cardboard ................................................................... Biology 17753 83.2 12 Support rods, 120 mm ............................................................................ Biology 17761 83.3 8 Connecting cubes ................................................................................... Biology 17788 83.4 6 Cell lids ................................................................................................... Biology 17745 83.5 1 Dropper, plastic .............................................................................. Biology, Heat 12875 83.6 2 Clamping rings ........................................................................................ Biology 17796

84 1 Float ................................................................................................................Air 47636

85.1 1 Suction flask with lid, 90 ml, plastic .................................................................Air 47563 85.2 1 Pipe cap for suction flask .................................................................................Air 47849

86 1 Funnel for suction flask, 60 mm dia. ................................................................Air 47571 87 2 Candles in metal holders ............................................................Heat, Chemistry 47911 88 1 Base box with lid and membrane slide ........................................ Sound, Biology 19390 89 1 Erlenmeyer flask, glass, 25 ml, heat-resistant ...............................Heat, Chemistry 12832 90 1 Food colouring, blue .........................................................................Heat, Water 12913

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Illustrated packing diagrams (bottom layer)

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Illustrated packing diagrams (bottom layer)

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List of components


91 1 Balloon valve ...................................................................................................Air 47660 92 1 Beaker, graduated, 100 ml, plastic ...............................................Heat, Air, Water 12794 93 2 Beakers, plastic, with bore .........................................................................Sound 25187 94 5 Balloons ..........................................................................................................Air 47725 95 1 Propulsion vehicle ...........................................................................................Air 47644 96 2 Instrument string pegs ..............................................................................Sound 19403 97 1 Bridge-shaped stand with hole ...................................................Heat, Chemistry 12824 98 2 Suction cup hooks ...........................................................................................Air 47709 99 1 Air-cushion disc ...............................................................................................Air 47652 100 1 Rubber stopper with bore .............................................................................Heat 12840 101 1 Mini-darkroom (stored between lid of the box and foam) ........................... Light 13820

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I. IntroductionThis set of equipment was developed for schools which want a small but eas-ily portable collection of teaching materials for experiments to accompany basic science courses.

The value of the General Science Kit for teachers lies in the ease of use and reliability of the equipment for the suggested experiments. Teaching aims can be dependably realized through demonstrations and pupils can also use the equipment (under teacher super-vision) to perform their own experi-ments.

Advantages of the General Science Kit

•clarityandsimplicityoftheexperimentalset-ups

•easyconstructionandreliableperformanceoftheequipment

•long-timedurabilityofallparts

•well-organizedarrangementoftheequipmentintheportablekit.

An assortment of materials with descriptions of experiments has been chosen for the following teaching topics:

•Air

•BalancesandEquilibrium

•Biology

•Chemistry

•ElectricalCircuits

•Heat

•LightandShadow

•MagnetandCompass

•SoundandTone

•WaterPurification

•WindandWeather

The illustrated packing diagrams together with illustrations of the mate-rials needed to carry out each experiment facilitates work with the General Science Kit.

Please note: Some experiments of the General Science Kit use an unshielded flame or an immersion heater as heating source. Therefore all experiments have to be accom-plished with a maximum of accuracy and cautiousness to prevent accidents like burns or scalds.

Heated elements must cool down before being restored in the kit.

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II. Air

1 Materials contained to carry out experiments for topic “Air”

1 13731 Plastic plate, white (4.6)

2 19454 Plastic tubes, 630 mm long (35)

1 47687 Plastic tube, transparent, 200 mm long (37)

1 47865 Valve fork for propulsion vehicle (40)

1 17729 Multi-purpose container (60.1)

2 47695 Syringes with tube coupling, 10 ml (64)

1 47636 Float (84)

1 47563 Suction flask with lid (85.1)

1 47849 Pipe cap for suction flask (85.2)

1 47571 Funnel for suction flask, 60 mm dia (86)

1 47660 Balloon valve (91)

1 12794 Beaker, 100 ml, plastic (92)

5 47725 Balloons (94)

1 47644 Propulsion vehicle (95)

2 47709 Suction cup hooks (98)

1 47652 Air-cushion disc (99)

2 Special learning aims

Air occupies space

•Containerswhichappearemptycontainair.

•Airisabodywhichoccupiesspace.

•Thespaceinacontainerwhichisoccupiedbyaircannotbetakenupbyanother body at the same time.

•Aircandisplacewaterfromacontainerjustaswatercandisplaceair.

•Afluidcanonlyflowoutofacontainerwhenairisabletoenterit.

•Aircanbecontainedwithinothersubstances.

Air exerts a force

•Aircanbecompressedandwillexpandagain.

•Theforceofcompressedaircanbeusedtoliftanobject.

•Theforceofanaircurrentcanbeusedtopropelanobject.

•Whenairisfilledintoanobjectmadeofelasticmaterial,thespring-forceor cushioning of the air increases (with the quantity) as more air is com-pressed within that object.

•Rearwarddischargeasapropulsiveforce(thrust).

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•Aninteraction(reciprocity)existsbetweenover-anddepressure.

•Airactsasaresistantforceagainstbodieswhicharemoving.

3 Underlying Principles

The Earth’s Atmosphere and its Composition

Just as other celestial bodies, our earth possesses an atmosphere (Greek: atmos = vapour, sphaira = ball). In the earth’s case, this extends to a height of over 1,000 km (600 miles). This huge “covering” around the solid mass of earth consists of air which becomes thinner the further away it is found from the earth’s surface, until it finally – consisting only of single stray molecules – merges into outer space (i.e.: the sun’s own atmosphere of rarefied gases).

The lowest and closest atmospheric layer to the earth is called the tropo-sphere, which extends to a height of about 11 km. Within this layer, the temperature drops to a low of about –70 °C. Practically all weather activities take place here, and almost all water vapour in the atmosphere is contained in this layer. The air is a mixture of gases. The percentages of its individual constituents remain the same up to a height of 100 km (60 miles) above the earth’s surface. One exception to this, however, is water vapour, which is mainly present in the layer closest to earth, the troposhere.

Air is a Body

In physics, the term “body” signifies something from inanimate nature – a mass of matter distinct from other masses – like a stone, a quantity of water, or a bubble of air. Body and matter do not mean the same thing. A certain body can consist of different substances or matter. All bodies take up a certain space. We differentiate between solid, fluid, and gas-like bodies. Solid bodies maintain their form and volume, for the most part; fluids main-tain only their volume, and gas-like bodies may easily change in form and

Solid bodies may displace fluids.

Air and other gases may displace fluids.

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volume. An age-old rule of physics states: No two bodies can occupy the same space. That does not exclude the possibility that bodies of water or air may be found inside a sponge. The body “sponge” contains empty spaces (hollows) which can be occupied by other bodies. If water enters a sponge, it displaces the air. If a stone falls into a bowl of water (or some other fluid), it displaces the water and the level of water in the bowl rises or runs over. Air and other gases may displace fluids, too.

Atmospheric Pressure

Under normal conditions, one litre of air weighs about 1.3 grammes. If one imagines an area of a square meter marked off at sea level on the earth’s surface, the column of air directly over it would have a weight (a mass) of about 10,000 kg, which is equal to the weight (the mass) of 10 cubic meters of water. The corresponding force of weight equals approximately 100,000 Newton (105 N). The international measuring system measures air pressure in “Pascal”.

Rule: one Pascal = 1 Pa = 1 N/m2

Thus, the air pressure at sea level equals about 105 Pa. This amount is also called 1 bar or 1,000 millibar (mbar). The German physicist, Otto von Guericke, was able to demonstrate the effect of air pressure as early as 1656 by using his “Magdeburg Hemispheres”. Two halves forming a hollow sphere were set together and pumped empty of air to make a vacuum. The two sides, devoid of all air within, were pressed together so firmly by the outside pressure of the atmosphere, that 16 horses could not pull them apart. Only when von Guericke reopened the valve through which the air had first been pumped out, did the two halves fall apart by themselves.

4 Notes on the Materials

The balloons contained in the General Science Kit are made of a special rub-ber compound which assures greater surface tension than with conventional balloons. A longer, steadier expulsion of air is achieved by this, guaranteeing better performance in the experiment. In addition, these balloons may be used again a number of times.

The balloon valve is an aid in blowing the balloons up and allow the balloon to be attached to the fork-like valve holder on the propulsion vehicle.

First, the mouth of the balloon is slipped over the end of the valve leading to the bellows. To blow up the balloons, one hand should hold the other end of the valve between the lips, while the other hand is used to press the bel-lows open and together. When the bellows are pressed together, the valve is closed, and no air can escape from the balloon. Then the balloon valve can be mounted (while the valve is shut) between the fork of the valve holder atop the propulsion vehicle or inserted into the stem-hole of the air-cushion

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disc. At this point, the bellows may be pulled apart to allow the air to flow out. Sometimes excess moisture collects in the valve, and the bellows may stick together. A simple cleaning under water, leaving the bellows apart to dry, will suffice. Please clean valve and tube, by using disinfectant tablets dissolved in warm water or by rinsing them under hot water.

The syringes with tube coupling are made with special plungers for contin-ued use. If a syringe should become difficult to operate after a long storage period, lubricating it with a drop of silicon oil can aid in returning it to its original condition.

5 Experiment

5.1 Air occupies space

5.1.1 Containers which appear empty contain air.

Experiment 1

All pupils have held an “empty” bottle under water at some time and have delighted in the resulting air bubbles. The first experiment can build upon that experience. The following questions need to be answered with the pupils:

•Whatdidweseeandhear?

•Wheredidtheaircomefrom?

•Werethebottlesreallyempty?

At this point we can take the first step toward recognizing that seemingly “empty” bottles actually contain air. When an “empty” beaker is submerged up-side down in water and slowly turned around in the opposite direction, we can see air bubbles escaping. This experiment works better with a container having a narrower opening – such as the suction flask. The suction pipe is first sealed off with the cap. When the flask is held in a tilted position under the water, with the opening close to the water surface, air bubbles rise. Thus we can see that the apparently empty flask does contain air.

Note: The suction flask never becomes completely filled with water. Even when the container is filled close to the edge with water, the water level of the tilted flask can never exceed that of the container. A last bit of air will always remain in the flask.

Materials: 1 multi-purpose container (60.1) filled with water 1 suction flask (85.1) 1 pipe cap (85.2)

5.1.2 The space in a container which is occupied by air cannot be taken up by another body at the same time.

Experiment 2

The pupils know that water, oil, and other fluids can be filled into a bottle by using a funnel. Some pupils, perhaps, have already discovered that fluids moved more slowly into a container when the funnel was fitted too snugly in the mouth of the bottle. In order to show that air can prevent water from entering a container, we shall insert the funnel in the lid opening of the suc-tion flask (slight twisting may be necessary). Close the suction pipe using

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the cap. Water must be poured quickly into the funnel using the beaker. At first, a few drops of water will flow into the flask. But then the air pressure at the opening of the flask reaches a point of equilibrium with the pressure of the water in the funnel, so that neither can the air escape from the flask, nor can any more water pass through the opening.

Note: If one were to pour the water in the funnel very slowly or drop by drop, the air inside the flask would be able to escape simultaneously through the funnel, and the experiment would fail. It is not easy for the pupils to find an explanation for this strange phenomenon that prevents water from flowing through a funnel. Explanation attempts like: “The water drops clog the funnel” or “The water molecules don’t allow the air molecules to pass through” may be tolerantly accepted as correct at this stage.

Materials: 1 suction flask (85.1) 1 pipe cap (85.2) 1 funnel (86) 1 beaker (92) filled with water

Experiment 3

Why the water cannot flow into the flask can be seen more clearly and better understood by placing a plastic tube on the end of the suction pipe instead of the cap. The tube is first bent double before the water is added – as in the previous experiment – to the funnel. After the funnel has been filled with water, quickly dip the end of the plastic tube into the container filled with water. The pupils see that at the same time that water is flowing into the flask through the funnel, air bubbles are escaping from the plastic tube. Pupils will be convinced through this experiment that the water could not flow into the flask before the air inside had found an escape opening.

Materials: 1 plastic tube (37) 1 multi-purpose container (60.1) filled with water 1 suction flask (85.1) 1 funnel (86) 1 beaker (92) filled with water

Experiment 4

Close the lid of the flask using a finger and press the entire flask completely under water in a horizontal position (the suction pipe must be submersed and pointing to the side or downward). Some pupils will surely assume that the water will enter into the flask through the open suction pipe. Yet the air in the flask prevents this from happening. Repeat the experiment and this time remove the finger from the lid of the flask under the water. The pupils witness how water now rushes into the flask and how the air escapes in streams of bubbles when the lid opening is held slanted upward, almost reaching the surface, or when the suction pipe opening is pointing upward, again just below the water’s surface.

Materials: 1 multi-purpose container (60.1) filled with water 1 suction flask (85.1) without pipe cap

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5.1.3 Air can displace water from a container just as water can displace air.

Experiment 5

If it is possible – as we saw in the first experiment – for water to displace air from a bottle, then it should also be possible to demonstrate in reverse that air can displace water from a container. Fill the multi-purpose container with water. Lay the beaker into the water. Under water place the float inside the beaker and turn the beaker upside down. When one blows air into the beaker through a tube, this air displaces the water. The continuous fall of the water level inside the beaker can easily be seen with the float.

Note: The beaker must be held down during the entire experiment. It is also advisable to view the experiment from the side, since reflection of the beaker will impair good observation of the water level from above.

Materials: 1 plastic tube (37) 1 multi-purpose container (60.1) filled with water 1 float (84) 1 beaker (92)

Experiment 6

This experiment has a surprise in store for the pupils, which will motivate them more to think about the possible causes of this amazing result. Stuff a crumpled portion of tissue into the bottom of the beaker in such a way that the tissue paper will not fall out when the beaker is held upside down. Before the beaker is immersed in the multi-purpose container with the open-ing facing downwards, the teacher should have the pupils predict what will happen to the tissue. Experience has shown that the class will be divided in their opinions as to whether the tissue will get wet or not. If the experiments 2–4 have been conducted beforehand, the pupils will be able to formulate a first hypothesis – based on knowledge gained from their previous observa-tions – before the experiment is actually carried out. The experiment then provides a testing ground for these hypotheses.

Materials: 1 multi-purpose container (60.1) filled with water 1 beaker (92)

Additionally: ½ tissue paper

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Experiment 7

Fill the multi-purpose container with water so that the funnel can be com-pletely submersed with the small opening pointing upwards. A tube is in-serted through this opening so that air can be blown into the funnel, forcing out the water. During this entire procedure, the funnel must be held down to the bottom of the container. Otherwise it will be forced up to the surface.

Note: The pupils should be made aware that this physical experiment has a technical application when work has to be carried out under water using a so-called diving bell. A bottomless iron box is sunk into the water, and air forced down to it through tubes and pipes, in order to prevent water from entering. In the air-filled space of the box, divers can work without the need of additional breathing devices, after they have become adjusted to the increased air pressure within. Once the pupils have learned that no other substance can occupy a space which is already occupied by air, and conversely that air cannot occupy a space occupied by another substance, both of the following experiments should stimulate them to think a step further about the observations they have made.

Materials: 1 plastic tube (37) 1 multi-purpose container (60.1) filled with water 1 funnel (86)

5.1.4 Air can be contained within other substances

Experiment 8

The teacher assigns the task of working out an experimental procedure which will test whether air is contained in these items. The pupils discover that one must place the objects in water and observe whether air bubbles escape from them. This experiment challenges the pupils to think about where the air bubbles could be coming from. The simplest explanation might be: “The air was inside the brick, inside the soil (and so on)”. A more exact statement could be: “There were small holes (pores) within the brick (or soil, etc.) and these contain the air.”

Materials: 1 multi-purpose container (60.1) filled with water

Additionally: 1 sponge, 1 brick, 1 piece of bread, soil, sand, grab, gravel

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5.2 Air exerts a force

5.2.1 Air can be compressed and will expand again.

Experiment 9

The pupils know that they must apply a force when they pump air into a bicycle tire. Surely they have already felt the force of compressed air, too, while pushing in the piston of the air pump and pressing their finger over the outlet of the air pump at the same time. For this experiment a plastic syringe is used instead of an air pump. Pull the plunger out of the syringe. Then close the outlet of the syringe with a finger as tightly as possible. Press the plunger and you will find out that you will not be able to push in the plunger of the syringe all the way. The graduation markings on the syringe allow a kind of measurement. The pupils observe that the plunger slides out again as soon as it is let loose, while the finger still remains pressed against the outlet. At first, this phenomenon may appear mysterious to some pupils. But they soon discover that the compressed air expands again and in so do-ing, pushes the plunger out of the cylinder.

Materials: 1 syringe (64)

5.2.2 The force of compressed air can be used to lift an object.

Experiment 10

Lay a book on top of a deflated balloon and then inflate it using the balloon valve. The force with which the air is blown into the balloon is enough to raise a book. In this way, the pupils become acquainted with the basic principle of hydraulic machines, and how it is applied, for example, in a hydraulic lift used at a garage.

Note: In order to be able to lift even larger books, it is possible – with a lit-tle skill – to fit the plastic tube on the end of the balloon valve. The added distance achieved prevents the book from sliding off the balloon and makes observation easier. It may be assumed that some balloons will burst during this experiment. The lifting force of compressed air works similarly when a flat tire is inflated on a bike. Pupils can observe how the entire bicycle is raised.

Materials: 1 plastic tube (35) 1 balloon valve (91) 1 balloon (94)

Additionally: books

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5.2.3 The force of an air current can be used to propel an object.

Experiment 11

A model fountain can be constructed using the suction flask and funnel. Fill the suction flask with some water. Then twist the funnel into the neck of the flask and push the short plastic tube down through the funnel, which must reach down below the level of the water. Place the other tube on the end of the suction pipe. The pressure which occurs in the flask, when air is blown into the side tube, forces water up the other tube. The fountain should be placed in a multi-purpose container to guard against overflow. The wash bottle of a chemical lab is designed according to this same principle, and serves to give out small amounts of water.

Materials: 1 plastic tube (35) 1 plastic tube (37) 1 multi-purpose container (60.1) 1 suction flask with lid (85.1) filled ¼ full with water 1 funnel (86)

5.2.4 Rearward discharge as a propulsive force (thrust).

Experiment 12

The term thrust could be new for many pupils. (Thrust is a force which de-pends on the rule that for every force, there is an equal and opposite reactive force.) At some time, everyone has blown up a balloon and accidentally let it go. The balloon flew in a zig-zag pattern throughout the room. The pupils receive another opportunity in class to refresh this experience. The pupils closely observe the flight paths of a balloon and reach the conclusion that in every case, the discharge of air and the balloon itself move in opposite direc-tions. Some pupils will already be thinking of rockets and jet aeroplanes.

Materials: 1 balloon (94)

Experiment 13

One can direct the propulsion of a balloon created by a rearward discharge to move in a straight line by mounting the balloon on a vehicle. The valve and balloon are inserted in the valve fork. Once the balloon has been inflated, the bellows of the valve are pushed together and the valve fork is set in the socket of the propulsion vehicle. Now the bellows can be opened and the discharging air propels the vehicle forward.

Note: The vehicle will roll best upon smooth, flat surfaces. Rugs and carpets are not as well-suited, they hinder the turning of the wheels.

Materials: 1 valve fork (40) 1 balloon valve (91) 1 balloon (94) 1 propulsion vehicle (95)

Air

2222

Experiment 14

The principle behind the air-cushion vehicle can be easily demonstrated and observed by using the air-cushion disc. Use an inflated balloon with the valve. When the valve is inserted into the air-cushion disc, the outflow of air moves the entire model across the table surface. The direction is determined by the position in the channel on which the force of the blown air is strongest. Oc-casionally it may be necessary to give the air-cushion disc a small shove.

Materials: 1 balloon valve (91) 1 balloon (94) 1 air-cushion disc (99)

Experiment 15

The tube is inserted through the small end of the funnel and the plastic wrap is drawn tightly over the top and held in place. Then the air is sucked from the funnel through the tube. The pupils observe that the plastic curves inward, and seems to be drawn into the funnel. The explanation for this must be developed very carefully in class discussion, for otherwise some pupils will not be able to follow. We can refer back to findings from previous experiments. The pupils know that air occupies a space and has the natural inclination to fill “empty” spaces. Air which is outside of the funnel – the same air which surrounds us – is not able to enter the funnel, because air is already in it. When we suck the air out of the funnel, there is less air in it than before, and the outside air can rush in. But because the plastic wrap is stretched out between the air in the funnel and the air outside, the air surrounding us presses in the plastic. At this point in the explanation, the teacher may introduce the term air pressure. When sucking from the tube is discontinued, the foil becomes smooth again, since air can enter the funnel through the small opening once more and press against the plastic from the inside.

Materials: 1 plastic tube (37) 1 funnel (86)

Additionally: plastic foodwrap

5.2.5 An interaction (reciprocity) exists between over- and depressure

Experiment 16

The principal of reciprocal action between over- and depressure can be demonstrated by using two syringes which are joined together by a tube. This experiment consists of two phases. Before connecting the tube, check that the plunger of one syringe (A) is pulled out as far as possible to the edge, and that the plunger of the other syringe (B) is pushed in all the way.

Phase 1: When the plunger of syringe A is pushed in, compressed air forces the plunger out of syringe B. The pupils are usually able to explain these observations correctly. The air in this system of connected cylinders is lightly pressed together by muscle power and is thereby able to push out the second plunger from the syringe.

Air

23

Phase 1 Phase 2

Phase 2: If we pull the plunger of syringe A back out again, plunger B will be pushed in. The outside air pressure, which is greater than the internal pressure, causes this to happen, since the air within the tube system was thinned out (rarefied) by pulling out plunger A, thereby reducing the air pressure inside.

Materials: 1 plastic tube (37) 2 syringes (64)

Experiment 17

The power of adhesion of suction cup hooks to smooth surfaces is based on the relation between internal and external pressure. This kind of hook might be known to the children from the kitchen and from the bathroom as a towel holder. By pressing the suction cup firmly against the wall, the trapped air is forced out, creating an depressure beneath the suction cup. The pupils say “The hook is clinging to the wall.” Because the outer pressure is greater than the inner pressure, the suction cup is pressed to the wall. The experiment works even better when the suction cup has been moistened beforehand. Affix the suction cup hook to smooth surfaces around the class-room (thick window panes, tiled walls, doors etc.). The suction cup hook has a load-carrying capacity of up to approximately 3.5 kg. This experiment leads on to the experiment by German physicist Otto von Guericke with the “Magdeburg Hemispheres”, an experiment which should, however, be reserved for higher grade levels.

A simpler version of the original experiment can be performed by using the two suction cup hooks.

Materials: 2 suction cup hooks (98)

Air

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Experiment 18

When the tip of the syringe is dipped in water and its plunger pulled out, water forces its way into the syringe. The air within the syringe has been rarefied and the air pressure pushing down on the surface of the water presses water into the syringe. Since a second substance, water, has been incorporated in this experiment, the pupils will need to think a step further to understand what is happening. If, however, the previous experiments were carefully and adequately explained, the pupils will be able to find the correct solution for this problem in class discussion.

Materials: 1 syringe (64) 1 beaker (92) filled with water

Experiment 19

Pupils owning an aquarium will be acquainted with the method for drain-ing out the dirty water without having to lift the heavy container. First, one end of the tube is held down in the water of the multi-purpose container. At the other end, suction is used to create an depressure within the tube. The water flows out of the container into the beaker, when the beaker and the tube end where the water flows out are held lower than the multi-purpose container. Before the beaker overflows, remove the tube from the multi-purpose container or stop the water by holding a finger over the tube end opening. At this grade level, the underlying law of nature can not yet be comprehended by the pupils.

Materials: 1 plastic tube (37) 1 multi-purpose container (60.1) filled with water 1 beaker (92)

Experiment 20

The well-known trick of magic, to have a postcard stick to the mouth of an overturned glass of water, succeeds only by virtue of the force of atmospheric pressure. In this experiment, a plastic plate is substituted for the postcard, which guarantees many repeat performances. The beaker is filled to the top with water and covered with the plastic plate. If the beaker and the plate are turned upside down, no water spills out, because the plate is pressed against the rim of the beaker and against the surface of the water. It is rec-ommended to carry out this experiment over the multi-purpose container. If the pupils have understood the effect of atmospheric pressure, they will no longer voice assumptions such as “The plate is sticking to the beaker”. They will be able to give the correct explanation now.

Materials: 1 plastic plate (4.6) 1 multi-purpose container (60.1) 1 beaker (92) filled to the top with water

Air

25

5.2.6 Air acts as resistant force against bodies which are moving.

Experiment 21

The pupils have received ample experience in the preceding lessons to know that air is not “empty space”, but actually consists of matter. Observations that all pupils have already made also contribute to a first notion of the particle structure of air. They know that it is difficult for them to run against the wind or to ride a bike in headwind. They also know that runners achieve better running times when they have the wind from behind than when there is no wind. Wind – or air in motion – must have a braking effect or as the case may be, an accelerating one; there must be something which brakes or pushes forward. The pupils let two equal-sized pieces of paper fall to the ground, preferably outside of the classroom; one of the pieces should be crumpled into a ball first. The ball of paper falls quickly, while the sheet of paper staggers and falls slowly to the ground. (At this point a comparison to the falling leaves of autumn can be made.)

Additionally: 2 equal sized sheets of paper

Balances and Equilibrium

2626

III. Balances and Equilibrium

1 Materials contained to carry out experiments for topic “Balances and Equilibrium”

1 15564 Set of weights in plastic box (29.0), containing:

10 15645 Weights, 0.1 g (29.1)

10 15580 Weights, plastic cubes, 1 g (29.2)

2 15572 Weights, brass, 10 g (29.3)

1 13561 Plastic box (34.0), containing:

1 13588 Copper ring (34.1)

1 13600 Rubber rod (34.2)

1 12590 Wooden disc (34.3)

1 13634 Brass screw (34.4)

1 13626 Aluminium rivet (34.5)

1 13677 Glass bead (34.6)

1 13650 Piece of porcelain (34.7)

1 13642 Carbon rod (34.8)

1 13685 Iron nail (34.9)

1 13669 Piece of string (34.10)

1 12565 Stone (34.11)

2 12751 Pegs, red (39.1)

1 12778 Peg, blue (39.2)

1 12760 Peg, yellow (39.3)

Beam balance, consisting of

1 15483 Balance beam (62.1)

1 15491 Adjustment rider (62.2)

1 15475 Balance column (65)

2 15505 Scale pans with bow (66)

1 26922 Dynamometer, 50 N/5000 g (67)

1 15548 Spring scale, capacity 25 g (69)

Seesaw, consisting of

1 15530 Seesaw beam (71)

1 15521 Seesaw bearing (74)


27


Equilibrium (Seesaw)

The pupils learn the terms “level” and “in (the state of) equilibrium” and apply these to different situations.

Balance Beam

Pupils become acquainted with the component parts and assemblage of a balance beam, as well as the achievement of equilibrium by aid of an adjust-ment rider (poise).

Pupils are able to decide by aid of the balance beam which of two items is lighter or heavier, or which items are of equal weight.

Roman Express Scale (single-arm scale)

Pupils learn that extra weight units are unnecessary with this type of balance – provided that a graduation of scale has been determined and the state of equilibrium established through the adjustment rider.

Weights

Pupils should come to terms – practically and mathematically – with the set of weights and be able to add together any combination of these weight-pieces as well as name these orally or in writing.

Calculator Balance

Pupils discover: the longer an “arm” (lever) is, the fewer the weights will be needed to bring the beam into equilibrium. The shorter an “arm” is, the more weights must be added (by putting them together).

Spring Balance

Pupils observe that the weight of a hanging object can be determined by the length of expansion of a spring.

3 Underlying principles

The historical development of the balance began already in very early times. Relics on the oldest balance were found in a prehistoric tomb in Egypt. This balance consisted of a balance beam made of reddish limestone, 8.5 cm in length, with holes at both ends and in the middle, through which cords had to be drawn in order to suspend the balance and to weigh goods. This balance is estimated to be about 5800 years old. Because of weights found dating back to the seventh millennium B.C., balances were probably already known much earlier.

Egyptians used their balances primarily for paying their tributes (taxes) as well as for weighing precious metals, but not in the sale or barter of food.

The Romans not only used balances (with equal arms), made of metal and set upon an axial pivot, but also Roman express scales, with unequal arms. From a historical point of view, it is not certain whether the Romans may be credited with the invention of this type of balance; it is, however, character-istic of the period and was found on many excavation sites.


2828

In a narrow sense, weight and mass measurements are carried out by use of the equal-arm beam balance as a sole means for comparing unknown masses with known ones (i.e. standard units of weight). Using the beam balance’s comparative method is especially simple, because it employs a lever with equal arms, thus, weight can be compared directly with power. A balance with unequal arms, such as the Roman express scale, employs only a small portion of the load weight in order to counterbalance.

The principal theorem for the lever applies equally to the two-pan (equal-arm) balance, the express scale, a seesaw, or to a calculator balance: load x load-to-fulcrum arm = effort x effort-to-fulcrum arm (in a state of equi-librium). The unit of mass in the metric systems is the kilogramme (kg). 1 kilogramme is the mass of the “original kilogramme” of a cylinder made out of platinum-iridium alloy, which is preserved in the Bureau International des Poids et Mesures in Sèvres near Paris. 1 kg = 1,000 g (grammes), 1 g = 1,000 mg (milligrammes). The unit for power, also of weight power is called Newton (N). 1 Newton is the power which gives a mass of 1 kg acceleration of 1 m/s², thus 1 N = 1 kg x 1 m/s². A body with a mass of 1 kg exerts on the earth’s surface a weight power (directed vertically down-wards) of 10 N.

The spring balance is also known to physicists as a dynamometer (67).With the Newton scale, one can find the weight power of a body, but not its weight. The power with which a body is drawn to earth, in other words its weight power is compared with the necessary power to deform a spring. From weight power, however, one can usually determine the weight or mass of a body, so that, indirectly, weight also can be determined with a spring balance.

4 Experiments

4.1 Experiment 1 Seesaw

Set the seesaw bearing on a table with its knife-edge up, place the seesaw beam with numbered side up on the seesaw bearing and find equilibrium.

Plastic pegs may simulate “children” on the seesaw.

Fasten pegs in different positions on seesaw beam and try to find equilibrium (e.g. one peg on right hand side in position no. 4 – one peg on left hand side in position no. 4, two pegs right hand side position no. 2 – one peg left hand side position no. 4).

One “child” also can seesaw by itself, if the seesaw beam is shifted into ap-propriate position.

Materials: 2 pegs, red (39.1) 1 peg, blue (39.2) 1 peg, yellow (39.3) 1 seesaw beam (71) 1 seesaw bearing (74)


29

4.2 Experiment 2 From seesaw to balance

Slide seesaw beam (without pegs) through opening in seesaw bearing as shown in illustration. (Consider the arresting device on one side of the seesaw bearing). Place seesaw bearing with inserted seesaw beam on column.

Find equilibrium by moving seesaw beam within seesaw bearing. Thus the concept “equilibrium” and “central pivot” can also be made clear in a verti-cal-edge position.

Materials: 1 balance column (65) 1 seesaw beam (71) 1 seesaw bearing (74)

4.3 Experiment 3 Beam balance

Place beam on balance column. Lead weight should be on back side. If the balance beam should not move freely on the column, the forklike parts of the column may be bent farther apart – without fear of breakage. Equilib-rium can be found by shifting adjustment rider. Attach both scale pans and re-adjust the rider for equilibrium.

Note: the small connecting knife-edge at the top of the pan bows should be slipped through the opening at each end of the balance beam and rest upon the lowest point of the bearing notch.

Compare weights by placing small objects on both pans (lighter, heavier). Now the objects are weighed – their weight (in grammes) is determined.

Use the set of weights: aluminium squares = 0.1 g plastic cubes = 1 g brass weights = 10 g

The plastic cubes can be joined together, so that “weights” of 2 g or 5 g can be used. To open the box of weights, place firmly on a table (red side down) and press finger down upon the tab while lifting the corresponding edge of transparent casing. Pencils and postcards can also be weighed.

The four raised points on the rim of the pans prevent objects from falling off. Due to lead weight in the pointer, the balance beam comes to rest in a very short time. Each weighing process lasts only about 30 seconds although the balance will respond to weight changes as minute as 80 mg.

Materials: 1 set of weights (29.0) 1 set of small materials (34) 1 balance beam (62.1) 1 adjustment rider (62.2) 1 balance column (65) 2 scale pans (66)

Additionally: various other objects, pencils, postcards


3030

4.4 Experiment 4 Egyptian balance

Attach three cords to balance beam in the same way as shown on illustration. The principles of this construction now are identical with a model of an old Egyptian balance which consisted only of a suspended balance beam with cords hanging from each end.

For this model weights and items for weighing must also be hung onto the balance beam.

Materials: 1 balance beam (62.1)

Additionally: 3 cords

4.5 Experiment 5 Roman express scale

Slide seesaw beam into seesaw bearing. Attach one pan to seesaw beam. Put nail in the middle of three holes between seesaw bearing and pan. Now hold the balance by this nail and find equilibrium by sliding the seesaw bearing as a counterweight.

Insert a strip of paper under the seesaw bearing on the grooved side of the seesaw beam and press the nail point through hole and paper. The paper may be used to mark a scale – using the edge of the seesaw bearing closest to the nail as a point of reference.

Put one 1 g weight on the pan and find equilibrium by moving the seesaw bearing (counterweight). Then make a pencil mark to the left of the seesaw bearing. After placing one more 1 g weight on the pan and repeated move of the seesaw bearing make the next pencil mark. Now by means of this small self made g-scale small items may be weighed.

Materials: 1 set of weights (29.0) 1 set of small materials (34) 1 scale pan (66) 1 seesaw beam (71) 1 seesaw bearing (74)

Additionally: 1 strip of paper


31

4.6 Experiment 6 Spring scale with calibration

Place a strip of paper (13.7 x 0.9 cm) on flat part of tube of spring scale. Insert each end of paper strip under rim of caps. The strip can also be at-tached with glue or rubber bands.

Prepare your own scale by using set of weights as described in experi-ment 5.

Compare this scale with dynamometer scales (one side a scale in g, on the other side in N).

Attach one pan on hook of spring scale and weigh small items e.g. from set of small materials.

Materials: 1 set of weights (29.0) 1 set of small materials (34) 1 scale pan (66) 1 dynamometer (67) 1 spring scale (69)

Additionally: 1 strip of paper

4.7 Experiment 7 Calculator Balance (equal-arm lever)

Slide seesaw beam into seesaw bearing. Place them on balance column. Please note numbers on seesaw beam and put for example one cube (1 g) into hole no. 4 on the left hand side of seesaw beam. Now find equilibrium by adding cubes to the right hand side, e.g. 1 cube into hole no. 4 or 2 cubes into hole no. 2.

Find other combinations: the greater the distance from centre, the fewer cubes are needed for balancing.

Materials: plastic cubes (29.2) 1 balance column (65) 1 seesaw beam (71) 1 seesaw bearing (74)

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IV. Biology

1 Materials contained to carry out experiments for topic “Biology”

2 19225 Flower press components (1)

1 19012 Package of absorbent paper (2)

1 17630 Pair of tweezers (9)

1 17648 Pair of scissors (10)

1 17613 Triple magnifier (11)

2 17680 Test tubes, plastic (14)

1 17699 Test tube brush (15)

1 17656 Knife (24)

1 17621 Dissecting needle (27)

1 17710 Set of double dishes, plastic (55)

Set of germination unit (60.0):


1 18121 Root-separator dividing plate (60.2)

2 17737 Germination-chamber inserts (60.3)

Set of accessories for germination unit (83.0):

12 17753 Special absorbing cardboard (83.1)

12 17761 Support rods (83.2)

8 17788 Connecting cubes (83.3)

6 17745 Cell lids (83.4)

1 12875 Dropper (83.5)

2 17796 Clamping rings (83.6)

1 19390 Base box with lid (88)

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General activities

Students receive practice in

•Observingwiththeaidofamagnifyingglass.

•Dissectingandpreparingplantsandanimals.

Topic “Botany”

The germination unit including accessories covers a wide field of activities.

By examining and observing pupils get acquainted with following phe-nomena:

•Swellingforceofseeds.

•Growthofplantroots,stemsandleaves.

•Reactionofplantstolightandcontact-stimuli.

•Windingandclimbingofplants.

•Importanceofgrowthfactorsforplantssuchaslight,warmth,air,water.

Topic “Zoology”

With the transparent air-permeable lid the multi-purpose container is well-suited for use as small aquarium or terrarium for a short-term captivity and observation of small animals (e.g. small fishes, beetles and worms).

By observing small animals pupils become acquainted with their habits (movements, breathing, eating, behaviour).

Topic “Human Biology” (Teeth)

Comparative examinations of incisor and molar and explanation of caries as a result of inadequate tooth care.

3 Equipment information and activity suggestions

Triple magnifier (11)

The diameter of the lenses was especially chosen so that a burning glass effect could not be produced. The magnifier can be taken along on excursions, by hanging it from a cord around the neck.

The big lens amplifies 3 x, the middle one 6 x, the small lens 10 x.

Activity suggestions:

•Observingseeds,buds,blossoms,fruits,bulbs,stalks,andbarkintheirentirety and in longitudinal and cross-sections.

•Determiningthesizeofgranulesinsoilsamples.

•Observationsoflivinganddeadinsectsandothersmallanimals(anato-my, posture, organs of locomotion like wings and legs, mouthparts, and organs for seeing and feeling).

•Detailedexaminationsofanimals,e.g.aspider’spoisonfangs,ortheeye of a maybug.

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•Examiningbirdfeathers.

•Inspectingbadlycleanedteeth,dandruffparticles,thumbprints,humanskin and hair.

Dissecting needle (27) and tweezers (9)

To prevent injuries, the dissecting needle should always be covered after each use with the transparent cap.

Use tweezers principally for grasping or holding objects to be examined or observed, especially very tiny objects, instead of using your fingers or hands.


•Openinganddissectingseeds,buds,andblossoms.

•Transplantingseedlingsintothegerminationboxorintotheearth.

•Settingoffprocessesofpollinationandcontact-stimuli.

•Analysingnests,pellets(casting)ofbirds,andinsects.

•Defininglayersofeggshells,observingandpuncturingeggs.

•Feedingsmallcaptiveanimals.

Knife (24)

This knife differs from an ordinary potato-peeling knife in having a shorter blade in relation to the longer length of the handle, thus allowing even the smaller hands of children to be able to handle the knife safely. To protect the table’s surface when using the knife, it is advisable to use one of the flower press components as work surface and base.


•Cuttingplantsandtwigs.

•Cuttinglongitudinalandcross-sectionsofpartsofplantswhichgrowabove or beneath the soil, and mushrooms.

•Peelingfruits,bulbs,andseeds.

•Diggingoutplantsfromthesoil.

•Dissecting.

Special scissors (10)

Each of the scissors has a pointed and a blunt blade end. When cutting sur-faces, the blunt end ought to be on the underside, so as to prevent damage to other underlying parts.


•Cuttinganddissectingstalksandotherpartsofplants.

•Cuttingoutleafshapes(patterns)outofpaper.

•Examinationsofeggs.

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Flower press components (1)

Also to be used as work surface and air-permeable lid for the multi-purpose container.


•Preservationanddissectionexperiments.

•Observationsofsnails(Putasnailonthesmoothareaoftheworksurface and watch it from underneath while it is eating or crawling), caterpillars, etc.

Flower and leaf press (1)

Instructions for assembling: Lay both flat surfaces together with the pro-truding “feet” facing opposite ends. Each object to be pressed should be kept between two pieces of absorbent paper (2). About 60 cm of cord tied around the cord holders is sufficient to firmly pull together the pressing surfaces, even when there are many layers. If only a few specimens are to be pressed, lay some additional sheets of newspaper between the absorb-ent paper, to help accelerate the process of evaporation. If many specimens (about 12 layers) are placed on top of each other, it is advisable to tighten the cord from time to time. Should the specimens be very moist, it is useful to replace the old absorbent papers with fresh ones after a short time.


•Constructinganherbarium.

•Pressingflowersandotherplantpartswithoneandtwocotyledons(seed leaves) for comparison.

•Identifyingdifferencesintheshapesofleaves(e.g.wildflowers).

•Comparisonofflowerpetalsofpeasandbeans.

•Classifyingthepetalsofaplantaccordingtotheirsize(e.g.comparisonof a fading garden rose and wild rose).

•Comparisonoftheleavesofonetypeofplanttakenfromdifferentloca-tions (dandelion, plantain, lady’s smock).

•Pressingdifferentkindsofgrass,earsofgrains(differentiationofspe-cies), and roots.

•Demonstratingtheprocessofprogressiveleafcolouringinpressedleaves.

•Demonstratingdifferentstagesofgrowthofgerminatingplants(e.g.bean, wheat) by pressing every day or every second day a germinating plant.

Plastic test tubes (14)

May not be heated over fire. If necessary, they can be warmed up in a water bath.


•Observingplantgrowthwithandwithoutwater,aswellaswithandwithout roots.

•Cultivatingcuttingsandslipsfromplants.

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•Experimentsonplantnutrition(e.g.distilledwater,nutritiveliquids).

•Comparativeobservationsofdifferentplantskeptintheclassroom.

•Experimentsonassimilation.

•Experimentsonthefunctionandactivityofroots.(e.g.putoneplantinto water by its roots, and another by its leaves. Compare them after a few hours.)

•Experimentsonplanttranspiration(twoplantsofequalsizeareputinto separate glasses of water; smear the undersides of the leaves of one plant with oil to close the pores. Cover the surface of the water in both glasses with a thin layer of oil to prevent evaporation.)

Base box with lid (88)

Used as test tube holder.


•Long-termandcomparativeexperiments.

Brush for cleaning test tubes (15)

For cleaning the test tubes.

Double-dishes (55)


•Creatingahumidchamberforgerminationexperiments,insertmois-tened absorbent cardboard strips (83.1) or cotton, for use with seeds and cut stems of different plants.

•Observingmouldgrowingonleaves.

•Experimentsonthedecompositionofleaves.

•Observingtheejectionofsporesfromthecapofamushroom.

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83.5

83.4

60.2

83.3

83.2

60.1

60.3

83.6

83.1

4 Description and use of the germination unit and its accessories

Multi-purpose container (60.1) and germination-chamber insert (60.3) with clamping rings (83.6)

One or two germination-chamber inserts can be put into the multi-purpose container. These inserts consist of two halves and they are held together by clamping rings.

Special absorbing cardboard (83.1)

The absorbing cardboard is impregnated with a special liquid that prevents mould, even when it is kept wet over a long-term experiment.

Cut some of the enclosed special absorbing cardboard pieces into long strips with a width of 1 cm. Push an absorbing strip down through the “wavy” slits on the bottom of each germination chamber cell, until the cardboard touches the bottom of the container.

These absorbing cardboard strips should be taken away as soon as the roots have grown into the water. Put several seeds of one sort into each chamber cell (in order to be able to remove non-germinating seeds without affecting the passage of time of the experiment.) Small seeds are placed next to the special absorbent cardboard strips, to prevent them from slipping though the chamber slits. A pair of tweezers may be used to move the seeds. Take care not to squash or damage the seed with the pointed tips of the tweezers. Then pour water through the water hole opening. The water level should reach the chamber slits.

Dropper (83.5)

The dropper is used for occasional moistening of the seeds, and is always kept in one of the water hole openings when not in use. It is advisable to continually refill the water, so that the roots and absorbing cardboard always remain in water.

Please note: After a dropper has been used for distributing oil, it should be cleaned with warm water.

Root-separator dividing plate (60.2)

The root-separator dividing plate is placed between both germination cham-ber inserts to prevent a tangling of the roots.

Cell lids (83.4)

During the period of germination, close the chamber cells with the plastic cell lids (greenhouse effect).

Support rods (83.2) and connecting cubes (83.3)

The yellow rods can be used as supports for the growing plants after the cell lids have been removed. With the help of the connecting cubes, it is pos-sible to link several support rods into a trellis. The yellow rods are pressed into the horizontal and vertical flutes of the cubes. The four corner cells of the germination chamber inserts have square sockets for insertion of the support rods.

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Germination unit with multi-purpose container

(A) = multi-purpose container (60.1)

(B) = germination-chamber insert (60.3)

(C) = special absorbing cardboard (83.1)

(D) = support rod (83.2)

(E) = connecting cube (83.3)

(F) = cell lid (83.4)

(G) = dropper (83.5)

(H) = clamping ring (83.6)

A

B

G

C

F

H

E

D

5 Botanical activities and experiments with the germination unit and the germination-chamber inserts

In the multi-purpose container with the germination chamber inserts, one can observe the water absorption or swelling and germination of seeds, growth and development of plant parts, and their reactions to specific en-vironmental factors. The following experiments and long-term observations can be carried out:

5.1 Growth of plant parts: roots and shoots (geotropism)

Peas are placed in a few germination chamber cells and cereals (barley or rye) are put in others to pregerminate. In doing this, it is best to have several seeds in each cell, to be able to sort out the poorer seeds after pregermina-tion. The remaining ones should be left in the cells, where the growth of the roots, stems, leaves and stalks can be observed. The pupils discover that the roots force their way through the slits on the bottom of each cell and grow in a downward direction (positive geotropism) and that pea stems and leaves and the stalks of cereals grow in an upward direction (negative geotropism). This is a question of the influence of gravitational force. To have a better understanding of this, one should put the germination unit in a dark place in a slanting position (lay something underneath one of the narrow sides) to observe that the roots again grow in a downward direction – in this case at a slant to the germination chamber – and that stems grow likewise in a vertical upward direction. After some time a layer of algae may form on the

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walls of the multi-purpose container. In this case, the germination chamber inserts must be carefully removed (so that the roots are not damaged) and placed aside. The multi-purpose container can then be washed with soap or with any synthetic detergent, and rinsed thoroughly until all the soap’s residues are cleared away. The container is then ready to be filled with fresh water, and the germination chamber inserts can be put back in again.

If one does not wish to plant small plants in flower pots for further observa-tion, it is recommended to replace the water in the multi-purpose container with a nutritive solution. When transplanting the plants, the germi-nation chamber inserts must again be removed; take off the clamping rings, and carefully pull apart the inserts halves. While doing this, tilt the inserts to the side where the support rods have been inserted, so that plants which are not to be removed do not accidentally fall out while separating the inserts.

5.2 Observation of phototropism in plants

The barley and pea plants in the germination chamber cells are placed in front of the classroom windows. Usually on the next day, one can already see that the leaves and stalks have turned towards the direction of light, if the sun has been shining (positive phototropism). On cloudy days, this reaction takes a bit longer. Moreover, if the exposure to the sun is intense one can even observe that the roots have turned away from the direction of the light (negative phototropism).

5.3 Observation of winding and climbing in plants

Since the germination chambers can also be equipped with trellis rods, it is possible to grow scarlet runners or other runner beans in a nutritive solution and observe the winding of the plants and how they climb up the trellis.

5.4 Development of a plant: from the flower to the fruit

The topic “growth of plant parts” is broadened through the observation that the fruit of plants develops out of the flower. For this purpose, beans are cultivated in the germination unit; the plants receive support, if needed, from the trellis rods.

5.5 Different growth determinants of a plant

By comparative observations students become aware of the importance of different growth determinants:

Water factor

Swelling and germination experiments with peas and beans – with and without water.

Soil factor (nutrient salts)

Growth experiments with cress and peas, in water, in soil and in a nutrient solution.

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Air factor

Swelling and germination experiments with peas exposed to the air and under airtight conditions. Drop some of the seeds into water, in order to observe the germination here as well. Nearly all of the seeds do not germi-nate. The addition of air is consequently also necessary for germination to take place. (Even seeds “drown”, when they cannot breathe.)

Warmth factor

Germination and growth experiments with cress or peas left in a room (room temperature), and in a refrigerator.

Light factor

Germination and growth experiments with peas, beans, cress, or Spanish vetch, pumpkin and corn. Experiments in a light room and in darkness (card-board box or a closed cupboard); observe the green colouring (or absence of it) and phototropism. One can observe that not all seeds germinate as well in darkness as they do in light conditions. Some seeds germinate and plants shoot up much more quickly in the darkness (beans), whereas others do not germinate in darkness at all. Some other plants do not germinate under light conditions. Comparisons between plant growth which has taken place in darkness and in light show that the plants which grew in the darkness pos-sess a pale colouring. Also the shape of the leaves is longer and narrower in contrast to the plants which were set out into the sunlight.

6 Botanical application of the multi-purpose container without the germination-chamber insert

The multi-purpose container can be used for experiments with or without the lid after the germination-chamber inserts have been taken out.

6.1 Reaction of plants to light and contact-stimuli

Remove the germination chambers from the container, fill the container with earth and plant common sorrel and daisies in it. Place the plants in the sun or outdoors. One can observe that the leaves of the common sorrel close when the sun is shining on them whereas the flowers of the daisies open up. The contrary behaviour of both plants can also be observed in the shade or during cloudy weather (or in a dark cupboard or cardboard box). Finally, it can be demonstrated that common sorrel reacts to contact-stimuli. When one sprinkles water on the leaves with a watering can, strews sand on it from a distance, or touches it firmly several times with some object, the leaves of the plant fold down after a few moments.

Biology

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6.2 Further experiments without the germination-chamber inserts:

•Germinationexperimentssettingseedsintodifferentdepthsofthesoil.

•Growthexperimentsonseedsandplantsunderdifferentconditions(light, warmth, water, sand, soil, sawdust, peat).

•Experimentsonwaterabsorptionandstorageinpeatmoss.

•Observationsofthegrowthofawater-weedinsandandinwater.

•Assimilationinplants(water-weed,hornwort).

•Observationsofrootandstalkcuttinginmoistsoil(e.g.couch-grass,dandelion).

•Experimentsontheswellingforceofseeds(coverthebottomofthebowl with a layer of peas, lay the root-separator dividing plate over them, and increase the pressure by adding a weight to the top. Water the peas. Observe and measure the changes which take place).

•Experimentsonthefunctionofplantleaves(observationsoffull-leaved,half-leaved, and bare twigs).

•Experimentsonevaporationinplants.

7 Zoological experiments

7.1 Activities and experiments using the multi-purpose container with the air-permeable lid

With the transparent air-permeable lid the multi-purpose container is espe-cially well-suited for short-term captivity and observation of small animals, beetles and insects (e.g. maybugs, flies or grasshoppers).

The lid slides over the side edges on both short ends of the multi-purpose container. The flat side of the lid should cover all sides of the container and sit perfectly on all edges.

The development of a caterpillar to a butterfly can be followed through long-term observation with the multi-purpose container. The pupils can easily find the eggs or caterpillars of the cabbage butterfly on cabbage leaves or the hairy caterpillars of the small fox butterfly on nettles and bring them to school (Leave cabbage or some nettles in the container).

The multi-purpose container is ideal for observing an earthworm and its “work”. Fill the container halfway with alternating layers of sand and soil. Place the earthworm on the top layer and close the container with the lid. (Leave a fresh leaf of lettuce in the container every day for the earthworm.) The pupils will quickly recognize that the layers become mixed together and loosened up by the “work” of the earthworm, thereby realizing the earthworm’s importance.

The container is also useful in the observation of snails. Since the container is transparent, the underside as well as the slimy trail of the snail can be clearly seen. (Feed the snail with lettuce.)

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Further activities:

•Short-termcaptivityandobservationofsmallwateranimalsand their larvae and of small fish, (swimming movements, breathing, eating habits, general behaviour).

•Observationinthebreedingofdrosophila(fruitflies).

•Collectinggall(gallnuts,oakapples,etc.)andobservationofthe development of animals which live in gall.

•Observingthemutationofthelarvaeofdragonflies.

•Observationofthetrappingdisguiseofadragonflylarva,asseen through the magnifier.

7.2 Experiments with the multi-purpose container without the air-permeable lid

•Experimentsdemonstratingthesurfacetensionofwater (pin, razor-blade, water strider).

•Notingthefloatingpositionsofarawandacookedegginwater.

Chemistry

43

Please note: Some experiments of the General Science Kit use an unshielded flame as heating source. Therefore all ex-periments have to be accomplished with a maximum of accuracy and cautiousness to prevent accidents like burns or scalds.


V. Chemistry

1 Materials contained to carry out experiments for topic “Chemistry”

1 19373 Test tube, glass, heat-resistant, approx. 160 mm long (13)

1 19381 Test tube holder (23)

1 13553 Nail, iron, 80 mm long (26)

1 19365 Beaker, heat-resistant, 50 ml (59)

2 47911 Candles in metal holders (87)

1 12832 Erlenmeyer flask, glass, heat-resistant, 25 ml (89)

1 12824 Bridge-shaped stand with hole (97)


Properties of matter

•Inchemistrytheterm‘matters’referstothematerialsofwhichobjectsare made.

Chemical changes

•Chemistry,oneofthenaturalsciences,investigatesthepropertiesofmatter and the changes that it undergoes.

Pupils learn that chemical changes can be initiated:

•byburningamaterial

•byheatingamaterial

•bycombiningtwomaterials

Pupils learn that

•oxygenisneededforcombustiontooccur.

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Please note:

Be cautious in using an un-shielded flame. Please read the instructions at the beginning of this chapter (page 43).

Please note:


3 Experiments

3.1 Experiment 1 Dissolving table salt

Place a small amount of table salt (NaCl) in a test tube. Add water and shake the test tube until the salt has dissolved. The solution is then heated until the water evaporates. The salt is left behind in the test tube.

Its material properties remain unaltered.

Materials: 1 test tube, heat-resistant (13) 1 test tube holder (23) 1 candle (87)

Additionally: table salt, water

3.2 Experiment 2 Igniting a splinter of wood

Set light to a splinter of wood (or a match). Blow out the flame before it reaches your hand. The splinter of wood no longer has the colour of wood, and has lost its elasticity and fibrousness, becoming instead black and brit-tle.

The properties of the splinter of wood have altered.

Materials: 1 candle in metal holder (87)

Additionally: splinter of wood or match

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45

Please note:


Please note:


1. 2. 3. 4.

3.3 Experiment 3 Heating sugar lumps

It is advisable to place some metal foil in the heat-resistant beaker before conducting this experiment because the residue is difficult to remove.

Heat a lump of sugar in a beaker. The original white and odourless sugar melts to a brown/black mass smelling of caramel.

Its properties have altered.

Materials: 1 beaker, heat-resistant (59) 1 candle in metal holder (87) 1 bridge-shaped stand (97)

Additionally: sugar lumps, metal foil

3.4 Experiment 4 Coating a nail with copper

A small amount of copper (II) sulphate is placed in the Erlenmeyer flask. Add water and shake until the blue crystals have completely dissolved. Then place a nail in the solution. After a few minutes you will observe that the part of the nail exposed to the solution has become red where it is coated with copper.

The materials in question have altered.

Materials: 1 nail (26) 1 Erlenmeyer flask (89)

Additionally: copper (II) sulphate, water

3.5 Experiment 5 What role does air play for combustion?

A heat-resistant beaker is placed upside down over a flame. Observe how the flame is soon extinguished. The oxygen in the air under the beaker is ex-hausted by the flame. The nitrogen that remains extinguishes the flame.

Combustible substance and oxygen are needed for combustion to occur.

Materials: 1 beaker, heat-resistant (59) 1 candle in metal holder (87)

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VI. Electrical Circuits

1 Materials contained to carry out experiments for topic “Electrical Circuits”

1 12735 Thermometer, –3 °C to +103 °C (6)

1 13480 Screwdriver (8)

1 13499 Lever switch (22)

1 13553 Nail, iron (26)

5 13448 Bulbholders (32)

1 13561 Materials for conductivity examination in plastic box (34.0), containing:

1 13588 Copper ring (34.1)

1 13600 Rubber rod (34.2)

1 12590 Wooden disc (34.3)

1 13634 Brass screw (34.4)

1 13626 Aluminium rivet (34.5)

1 13677 Glass bead (34.6)

1 13650 Piece of porcelain (34.7)

1 13642 Carbon rod (34.8)

1 13685 Nail, 50 mm long (34.9)

1 13669 Piece of string (34.10)

1 12565 Stone (34.11)

2 13464 Terminal clips (46)

1 13529 Spool of copper wire (20 m) with red plastic insulation (47)

1 13537 Spool of heating wire (20 m) with grey cotton insulation (48)

1 13545 Spool of copper wire (60 m) with transparent enamel insulation (49)

10 13430 Bulbs, 3.5 Volts, 0.25 Ampere (81)

1 13359 Battery, square, 4.5 Volts (82)

Electrical Circuits

47

Galvanic elementSquare battery


Introduction to the basic principles of electricity through simple experi-ments.

Answers are given to the following questions:

•Whatcomponentsbelongtoanelectricalcircuit?

•Whatisaparallelconnection?

•Whatisaseriesconnection?

•Howcanelectricalcurrentproduceheat,lightandmotion?

•Howdoesoneconstructanelectromagnet?


Generation of Current

Electrical current is mainly generated by means of generators or galvanic elements. Generators utilize electromagnetic phenomena for the purpose of converting mechanical energy into electrical energy. The generators in power stations are driven either by steam power (thermal power stations, also atomic power stations) or by water power by means of turbines. Gal-vanic elements (batteries) convert chemical energy into electrical energy. Basic components of a galvanic element are: a zinc can (negative electrode) containing a carbon rod (positive electrode). Inside the zinc container there is a mixture of water, magnesium dioxide, ammonium chloride and sawdust. The ammonium chloride serves as the electrolyte. Inside a 4.5 Volt flash lamp battery (square battery) there are three series-connected elements.

Process in the Circuit

If the two poles of a current source, e.g. of a battery, are conductively con-nected, then electrons flow from the negative pole through the line to the positive pole. This is called a closed circuit.

An electrical appliance included in this flow of electrons converts the electri-cal energy, according to its construction, into another form of energy e.g. light.

Electrical Circuits

4848

Parallel connectionSeries connection

For the assembly of an electrical circuit, connecting wires, a bulbholder and terminal clips can be employed.

A circuit can be conveniently opened or closed by means of a switch.

Electrical Connections

There are two ways of connecting several electrical appliances to a current source: the series connection (connecting in series) and the parallel connection.

In the case of the series connection both bulbs light up darker than with the parallel connection, because their individual resistances add up, so that the current drops correspondingly. If in a series connection one of e.g. two bulbs is unscrewed in its holder, then the other bulb also goes out.

In the case of the parallel connection, however, each lamp is in an individual circuit. For this reason one of the two lamps can be unscrewed without the other going out.

Conductors and non-conductors

Materials which conduct the electric current are conductors, those that do not are non-conductors.

Silver conducts very well, equally copper. Nichrome and constantan on the other hand are poorer conductors, they possess a high resistance.

The non-conductors (insulators) comprise plastics, dry wood, rubber, por-celain, glass, etc.

Filaments in bulbs generally consist of the hard-to-melt metal tungsten (melt-ing point: 3350 °C). To prevent the filament from being burnt, the glass of bulbs from 40 watts upward is filled with an inert gas (argon, krypton). The surface area of the filament effecting the undesirable heat dissipation is reduced by coiling the filament once or twice. A defective glass makes a bulb unserviceable, since the filament immediately burns when exposed to the air if current is flowing through it.

High-conductivity copper wire is generally used for power supply cables; those parts of an appliance serving the generation of heat, however, are provided with a resistance wire.

Electromagnetism

A magnetic field originates around a wire through which current flows, which can be increased by winding the wire into a coil. If an iron core is added, the magnetic force is concentrated still further; the result is an electromagnet which is effective as long as current flows through the wire. Most electrical appliances which generate a motion including the electric motor operate on this principle.

Electrical Circuits

49

Please note:

Check the copper wires before con necting them. The insulation at the wire ends must be stripped off !

4 Experiments

4.1 Experiment 1 Battery and bulb

Bulb and battery are joined conductively to form a closed circuit that the lamp lights up. The bulb will only light up if its two terminals are simultane-ously in contact with each one pole of the battery.

Materials: 1 bulb (81) 1 battery (82)

4.2 Experiment 2 The glass of the bulb

A defective glass makes the bulb unserviceable. In order to demonstrate this, the glass of a miniature bulb may be carefully crushed, avoiding the filament from being damaged. The lamp is then connected to the battery. With a brief flash the filament is burnt immediately. For this reason the air in the glass of the bulb is always pumped dry and filled with an inert gas (argon or krypton).

Materials: 1 bulb (81) 1 battery (82)

4.3 Experiment 3 Simple circuit

A bulb is connected to the battery by means of two connecting wires, two pole terminals and a bulbholder. This experiment requires two wires approx. 25 cm in length, which have to be stripped off the insulation approx. 1 cm at the ends. For cutting the wires an old pair of scissors will be sufficient. Stripping the wire may be done with the fingernails, since the insulation was chosen specially soft.

Materials: 1 screwdriver (8) 1 bulbholder (32) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 1 bulb (81) 1 battery (82)

Electrical Circuits

5050

Please note:


4.4 Experiment 4 The switch in the circuit

Electrical appliances will only operate if the circuit is closed. For closing and opening circuits, switches are used. Battery, switch and bulb in its holder are joined with connecting wires as shown in the illustration. When clos-ing the switch, the lamp lights up, when opening the switch it goes out. – A lever switch is used for the experiment, because its functioning can be observed well.

Materials: 1 screwdriver (8) 1 lever switch (22) 1 bulbholder (32) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 1 bulb (81) 1 battery (82)

4.5 Experiment 5 Series circuit

If two or more bulbs are connected to form a circuit, as shown in the illustra-tion, the result is a series circuit (connecting in series). The lamps will light up darker, than one lamp alone. If one of the lamps is unscrewed in its holder the other one will also go out.

Materials: 1 screwdriver (8) 2 bulbholders (32) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 2 bulbs (81) 1 battery (82)

4.6 Experiment 6 Parallel circuit

Two bulbs may also be connected to a battery as shown in the illustrations below. In this instance the lamps are connected in parallel with each other. They light up bright. If one bulb is unscrewed in the bulbholder, the other one continues to burn.

Materials: 1 screwdriver (8) 2 bulbholders (32) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 2 bulbs (81) 1 battery (82)

Electrical Circuits

51

Please note:


4.7 Experiment 7 Which materials conduct the electrical current?

An open circuit with light bulb, battery and three connecting wires is set up. The gap in the circuit is bridged alternatively with the small materials shown in the illustration.

The metals (copper, aluminium, brass, iron) and carbon conduct the electric current whereas stone, rubber, dry wood, porcelain, glass, plastics etc. do not; they are insulators.

Materials: 1 screwdriver (8) 1 bulbholder (32) 1 set of small materials (34) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 1 bulb (81) 1 battery (82)

4.8 Experiment 8 Electric current generates heat

Connect heating wire (length approx. 80 cm) to the battery and to the lever switch. Make connection between lever switch and battery by means of copper wire with red insulation. Wind heating wire into a coil. Close the circuit by pushing down the lever of the lever switch. A heating effect can be felt by touching the heating wire with the fingertips.

In order to measure the heat generation, wind the heating wire carefully round the thermometer bulb. When the circuit is switched on, the genera-tion will be noticeable on the thermometer.

Materials: 1 thermometer (6) 1 screwdriver (8) 1 lever switch (22) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 1 heating wire with grey cotton insulation (48) 1 battery (82)

Electrical Circuits

5252

Please note:


4.9 Experiment 9 The electromagnet

A wire coil with an iron core (nail) through which a current passes is an electromagnet. The large nail is wound with enamelled wire (length approx. 1 m) after transparent enamel has been scraped off the ends. A connection to the battery and the lever switch is made. The connection between lever switch and battery is made by means of connecting wire (red insulation).

Close the circuit with the lever switch and the large nail will get magnetized. Then position the small nail as shown. It is attracted by the large nail which functions as an electromagnet when the current passes through.

Materials: 1 screwdriver (8) 1 lever switch (22) 1 large nail (26) 1 small nail (34.9) 2 terminal clips (46) 1 spool of copper wire with red plastic insulation (47) 1 spool of copper wire with transparent enamel insulation (49) 1 battery (82)

Heat

53

VII. Heat

1 Materials contained to carry out experiments for topic “Heat”

1 12743 Thermometer, without graduation (5)



2 12859 Glass tubes, 220 x 7 mm (19)

1 12999 Atomizer (21)

2 12751 Red pegs (39.1)

1 12778 Blue peg (39.2)

1 12808 Insulating case (58) for beaker (92)

1 19365 Beaker, heat-resistant, 50 ml (59)


1 13111 Bowl with lid (61)

1 12875 Dropper, plastic (83.5)

2 47911 Candles in metal holders (87)

1 12832 Erlenmeyer flask, glass, heat-resistant, 25 ml (89)

1 12913 Food colouring (90)

1 12794 Plastic beaker, 100 ml, graduated (92)

1 12824 Bridge-shaped stand (97)

1 12840 Rubber stopper with bore (100)

Heat

5454


Pupils become acquainted with

•temperature,

•itsmeasurement,

•thethermometerscaleasdevisedbyA.Celsius,

•theprinciplesofevaporationandcondensation,

•thewatercycleonEarth.


Heat and thermometer

When solid bodies, liquids or gases are heated their volume (the amount of space that they occupy) generally increases. For example, when warmed by 1 degree Celsius (= 1 Kelvin), 1 litre of water and 1 litre of mercury both expand by 0.2 millilitres (= 0.2 cubic centimetres), alcohol by 1.1 millilitres (= 1.1 cubic centimetres).

When cooled, the volume decreases again. However, if water (under nor-mal pressure) is cooled, its volume only decreases until it reaches 4 °C (Cel-sius). If the water is cooled further to 0 °C its volume increases again. When water at 0 °C changes to ice at 0 °C there is a sudden increase in volume. This they cool and solidify.

Temperatures are measured using thermometers. Liquid thermometers consist of a liquid-filled container (the bulb) connected to a very narrow tube. If the temperature rises, the liquid will expand. The level of the liquid in the tube at any given time can be read from a scale. Thermometers are usually filled with alcohol or mercury.

On the Celsius thermometer scale the freezing point of water is marked at zero degrees Celsius (0 °C), and the boiling point of water at 100 degrees Celsius (100 °C). On the Fahrenheit thermometer scale the freezing point of water is shown as +32 °F and the boiling point of water as +212 °F. Read-ings in degrees Fahrenheit are still used in Britain and North America.

The clinical thermometer

Whereas outdoor, room and bath thermometers always show the tempera-ture to which they are being exposed, the clinical thermometer is a so-called maximum thermometer. In other words, once the reading has reached its highest level, it remains there.

This is achieved by means of a constriction between the bulb and the tube. As the mercury expands it is able to pass through this constriction, but as it cools it retracts, causing a break in the thread of mercury at this point. This enables a permanent reading.

Only by shaking the clinical thermometer the liquid is forced back through the constriction into the bulb.

Heat

55

Some selected temperatures in degrees Celsius (°C)

6000 surface of the sun

2500 filaments in a lamp

1535 iron melts

1063 gold melts

950 to 1200 flame of gas burner

800 match flame

357 mercury boils

327 lead melts

270 electrical soldering iron

220 smoothing iron (linen setting)

100 water boils

78 alcohol boils

57.8 highest air temperature ever measured on Earth

36 to 37 body temperature of healthy human being

0 water freezes

–39 mercury solidifies

–89.2 lowest air temperature ever measured on Earth

–180 air liquefies

–273 lowest possible temperature (absolute zero)

Evaporation

The conversion of a substance from the liquid state into the gaseous state is referred to as evaporation.

There are two methods of evaporation: boiling and vaporization.

If water is heated to 100 °C, bubbles rise to the surface because the water particles start moving rigorously as a result of the heat supply. The water “boils”. The rising bubbles contain an invisible gas: water vapour.

Vaporization is the name given to the process when a liquid evaporates at a temperature below its boiling point. In this case, only particles on the liquid surface enter the gaseous state.

Condensation

The reverse process to evaporation, i.e. the conversion of a substance from the gaseous state into the liquid state, is known as condensation.

Small droplets of liquid form from the invisible gas over the boiling water upon cooling and can be observed as a cloud or mist.

Heat

5656

Please note: Some experiments of the General Science Kit use an unshielded flame or an immersion heater as heating source. Therefore all experiments have to be accom-plished with a maximum of accuracy and cautiousness to prevent accidents like burns or scalds.


Please note:


4 Experiments

4.1 Experiment 1 Heating and cooling water

Fill the Erlenmeyer flask to the brim with (coloured) water. The rubber stop-per is then inserted in the flask. The glass tube is inserted in the hole in the stopper, which causes the water to rise in the glass tube. The level of the liquid in the tube is marked using the blue plastic peg.

Now place the flask, filled with water, on the bridge-shaped stand and heat it using a candle in a metal holder. As it is heated the level of the water in the tube rises, because its volume is increasing. The new water level is marked with a red peg.

To cool the flask, place it in the plastic beaker, which should be filled with cold water, and possibly ice cubes as well.

Materials: 1 glass tube (19) 1 peg, red (39.1) 1 peg, blue (39.2) 1 candle in metal holder (87) 1 Erlenmeyer flask (89) 1 food colouring (90) 1 plastic beaker (92) 1 bridge-shaped stand (97) 1 rubber stopper (100)

Additionally: 1 thermos flask containing cold water or ice cubes

4.2 Experiment 2 Heating and cooling methylated spirits (inflammable!!)

The Erlenmeyer flask is filled to the brim with coloured methylated spirits. Then the rubber stopper is inserted in the flask. The glass tube is inserted in the stopper.

Because methylated spirits is inflammable for heating the spirits we do not use any candles. Instead a beaker filled with hot water is placed in the insulating case.

Then the Erlenmeyer flask with rubber stopper and glass tube is placed in the plastic beaker. To cool the flask, place it in the bowl, which should be filled with cold water, and possibly ice cubes as well.

As it expands the methylated spirits rises up the glass tube. When it cools the level falls again. When heated, methylated spirits expands more than water.

Heat

57

Materials: 1 glass tube (19) 1 insulating case (58) 1 bowl, without lid (61) 1 Erlenmeyer flask (89) 1 food colouring (90) 1 plastic beaker (92) 1 rubber stopper (100)

Additionally: 1 thermos flask containing hot water (70 °C), 1 thermos flask containing cold water or ice cubes, methylated spirits

4.3 Experiment 3 How does a thermometer function?

The thermometer without graduation is alternately dipped into two beakers containing water at different temperatures.

The thermometer functions in the same way as the equipment set up in experiments 1 and 2: when it is heated the alcohol in the thermometer expands, and it contracts as it cools.

Materials: 1 thermometer without graduation (5) 1 beaker, heat-resistant (59) 1 plastic beaker (92)

Additionally: 1 thermos flask containing hot water, 1 thermos flask contain-ing ice cold water

4.4 Experiment 4 What is a thermometer for?

Fill the beakers and bowl with water at varying temperatures: approx. 55 °C, 25 °C and ice cold. Test the temperature by placing your hand in it.

Water at 25 °C feels cold if your hand has previously been held in hot water. However, if you first place your hand in cold water and then in water at 25 °C, the water feels warm.

If a thermometer is used to measure the temperature it will always indicate the same temperature in the lukewarm water, regardless of whether it has been held in hot or cold water beforehand. Therefore, thermometers have to be used for exact temperature measurements.

Materials: 1 thermometer, –3 °C to +103 °C (6) 1 beaker, heat-resistant (59) 1 bowl, without lid (61) 1 plastic beaker (92)

Additionally: 1 thermos flask containing hot water, 1 thermos flask contain-ing ice cold water, tap water

Heat

5858

Please note:

Be cautious in using the immer-sion heater. Please read the in-structions at the beginning of this chapter (page 56).

4.5 Experiment 5 The Celsius scale

The Celsius scale is defined between two specific temperatures, the melting point of ice (0 °C) and the boiling point of water (100 °C).

On a thermometer without graduation these two temperature points can be determined as follows: Fill a large heat-resistant beaker with water. An immersion heater is used to bring the water to boil.

Place the thermometer without graduation in the water and wait until the liquid in the thermometer stops rising. Mark this point with a red peg.

Then fill the plastic beaker or the bowl with water and ice cubes. Place the thermometer in the water and wait until the liquid in it stops moving. Mark this point with a blue peg.

Compare with the thermometer with Celsius scale, which shows 100 equal divisions between the marked two points (0 °C to 100 °C).

Materials: 1 thermometer without graduation (5) 1 thermometer, –3 °C to +103 °C (6) 1 red peg (39.1) 1 blue peg (39.2) 1 bowl, without lid (61)

Additionally: 1 thermos flask containing ice cubes, 1 heat-resistant glass beaker, 1 immersion heater, some water

4.6 Experiment 6 Taking temperature measurements and reading exercises

Both thermometers with a scale can be used to measure different tempera-tures e.g. classroom temperature, temperature of cold and warm water, hot tea, temperature of bulb after light has been switched on for a few minutes etc.

For reading exercises and entries the worksheet at the end of the chapter (page 60) should be photocopied:

Materials: 1 thermometer, –3 °C to +103 °C (6) 1 thermometer, –25 °C to +50 °C (7)

Heat

59

4.7 Experiment 7 Converting a liquid into a gas

Close the Erlenmeyer flask with the rubber stopper, invert it and place on the stand. Place a drop of Eau-de-Cologne or methylated spirits on the middle of the base of the flask using a dropper.

The drop becomes smaller and smaller until it is no longer visible. The liquid has vaporized/evaporated. It has turned into a gas.

A gas consists of tiny particles, invisible to the naked eye. However, it is some-times possible to smell these particles even when the liquid has evaporated completely, e.g. in the case of Eau-de-Cologne or methylated spirits.

Materials: 1 dropper (83.5) 1 Erlenmeyer flask (89) 1 bridge-shaped stand (97) 1 rubber stopper (100)

Additionally: Eau-de-Cologne or methylated spirits

4.8 Experiment 8 Water evaporates, vaporizes too

The Erlenmeyer flask is set up as in experiment 7 but now a drop of water is placed on its base. In this case too, the drop of water evaporates after a while.

Examples of water vaporization/evaporation in everyday life:

•Wetlaundrydries

•Rainwateroncarwindows (the drops gradually become smaller and smaller until the window is completely dry)

•Waterinanaquariumevaporates (water must be added from time to time)

Materials: 1 dropper (83.5) 1 Erlenmeyer flask (89) 1 bridge-shaped stand (97) 1 rubber stopper (100)

Additionally: some water

4.9 Experiment 9 Can a gas be re-converted into a liquid?

Add some hot water (at least 70 °C) to the Erlenmeyer flask. Close the flask with a rubber stopper.

The glass fogs up. The water particles which have evaporated deposit on the glass. A gas has been converted into a liquid.

Materials: 1 Erlenmeyer flask (89) 1 rubber stopper (100)

Additionally: 1 thermos flask or glass with very hot water

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Please note:

Be cautious in using the immersion heater. Please read the instruc-tions at the beginning of this chapter (page 56).

4.10 Experiment 10 What happens when steam cools down?

Fill a heat-resistant beaker with water and bring the water to the boil with an immersion heater. Now hold the multi-purpose container filled with ice cubes over the steam.

The water boils. Numerous particles escape from the water, some of which rise as gas bubbles (steam). The steam becomes mist (clouds) in the cooler air as the particles become more densely packed. Drops form on the cool base of the container. They condense.

Materials: 1 multi-purpose container (60.1)

Additionally: 1 large heat-resistant beaker glass or container, 1 immersion heater, 1 thermos flask with ice cubes, some water

4.11 Experiment 11 The water cycle

Water evaporates everywhere: Invisible water particles rise from the sea, from fields and forests.

These evaporated water particles condense where the air is colder and form (mist) clouds.

When the air becomes even colder or the wind moves these clouds to cooler regions, the mist particles unite to form larger drops which, because of their weight, fall downwards: It rains.

The water cycle is complete. The rain evaporates, the invisible particles rise etc.

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4.12 Experiment 12 How water particles unite

Fill the atomizer with water. Spray the water onto a window or blackboard from a distance of approximately 30 cm. The tiny particles from the atom-izer form a barely visible water cloud, but on the sprayed surface they unite after a while and form drops of increasing size.

Materials: 1 atomizer (21)


6262 Worksheet © Cornelsen Experimenta

Heat – Reading exercises

Write down the temperatures shown by the thermometers.

Light and Shadow

63

VIII. Light and Shadow

1 Materials contained to carry out experiments for topic “Light and Shadow”

1 13707 Slotted stand as cardholder (3)

1 13766 Card showing human figures (4.1)

1 13758 Cardboard, square, smooth (4.2)

1 13740 Cardboard, square, rough (4.3)

1 13715 Metal foil (4.4)

1 13839 Metal mirror (4.5)

1 13731 Plastic plate (4.6)

1 13723 Synthetic pane (4.7)

1 13693 Tilting mirror (63)

1 13812 Rod on base for casting a shadow (73)

1 13775 Electric torch with bulb (78)

2 39218 Battery, round, 1.5 Volts (80)

1 13820 Mini-darkroom (101)


By means of simple experiments answers are given to the following ques-tions:

•Whyareweunabletoseeinthedark?

•Howareshadowsformed?

•Whydoesamirrorreflect?


We distinguish between light sources of the first order (self-illuminating) and light sources of the second order (externally illuminated).

Light sources of the first order emit light that they themselves produce (e.g. sun, light bulbs, flames).

Light sources of the second order reflect only some of the light that falls on them. Self-illuminating objects are often divided according to the way the light is created, into natural sources of light (e.g. sun, stars, self-lucent animals) and artificial light sources (e.g. light bulbs, candles, fluorescent lamps). The most important and by far the most powerful source of light is the sun. Sunlight is produced as a result of atomic reactions (nuclear fusion), which release enormous quantities of energy, and some of this is irradiated in the form of light energy.

A light source emits light in all directions, and the beams of light travel in straight lines.

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Light only becomes visible when it strikes an object, and when some of it reflected by that object reaches our eyes. Light travels at a speed of approx. 300,000 km/s.

Light can pass almost unimpeded through a number of mediums (e.g. air, glass), and these are referred to as transparent. Most of the substances that surround us do not permit the passage of light, and these are described as being opaque.

Translucent substances allow light to pass through but at the same time they disperse it to such an extent that other objects cannot be seen clearly (i.e. opalescent glass, tissue paper). As we mentioned before, the rays from a light source travel in a straight line, and if they strike an opaque object, an area on which no light falls is created behind the object, i.e. an area in shadow. Light from a point produces a clearly defined shadow. Where there are several sources of light, or a broader source, some partly illuminated areas (half-shadow) and areas with no light (complete shadows or umbra) may be created. Solar and lunar eclipses are also examples of shadow formation.

The law of reflection states that a ray of light striking a plane surface is re-flected in such a way that the angle between the incoming beam and the axis of incidence is equal to the angle formed by the reflected beam and the perpendicular. The incoming light beam, reflected beam and perpendicular are all in the same plane. The light is always reflected in a certain direction by smooth surfaces (directed or regular reflection, mirroring). Objects with a rough surface reflect light in every direction (undirected, diffuse reflection). Dark surfaces reflect less light than bright surfaces.

All life on the Earth depends on the Sun, which irradiates enormous amounts of energy into the surrounding space, for example in the form of light and heat. It is a flaming ball of gas with a diameter of approx. 1.4 million km. The Sun is the largest, central body in our solar system. It is also the closest self-illuminating star to the Earth. Its average distance from the Earth is about 8 light minutes (1 light minute = 60 x 300,000 km). During one day the Sun appears to describe an arc, because of the rotation of the Earth. Each position of the Sun alters the direction of the shadow that it casts. This is the principle behind the sundial.

4 Experiments

4.1 Experiment 1 We cannot see anything without light

The mini-darkroom is set up as follows: the rear flaps 1 and 2 (2x) are folded over one another; the longer flap 3 is inserted in the remaining slit and, from the inside, attached by bending round the back panel.

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A number of small objects are placed in the mini-darkroom. Now hold the box in front of your eyes in such a way that no light can enter from the side. The objects cannot be seen. They only become visible when the electric torch is turned on and inserted in the mini-darkroom.

Materials: 1 electric torch (78) 1 mini-darkroom (101)

Additionally: Some small objects

4.2 Experiment 2 How are shadows formed?

An opaque object (e.g. an eraser) is placed on the table and illuminated at an angle from the side by the torch.

Light cannot penetrate the object. A shadow is formed behind it.

This area does not receive direct light from the torch.

Materials: 1 electric torch (78)

Additionally: 1 eraser

4.3 Experiment 3 Why does the shadow change position?

The rod, which is used to cast a shadow, is placed on the table and the light from the torch (without the reflector) is shone on it from the side. The rod casts a shadow on the table. If the position of the rod is altered, the shape and direction of the shadow also change.

Leave the rod in the same position and move the torch. This causes the direction and size of the shadow to alter; the shadow “wanders”. Thus we see that the direction and shape of the shadow depend on the shape of the object and on the location of the light source.

Materials: 1 rod on base (73) 1 electric torch (78)

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4.4 Experiment 4 Reflection from various materials

The slotted stand is used to hold, in succession, the various pieces of card-board, the plastic screen, and the synthetic pane, firstly on its own, and then with the metal foil placed perpendicularly behind it. The metal foil in combination with the screen or the pane serves as a mirror. Compare with metal mirror. Now examine how this mirror reflects light. The materials are illuminated by the torch from a number of different directions. We shall come to the conclusion: smooth surfaces cast the light in a particular direction (directional reflection); rough surfaces cause diffusion of the light.

Materials: 1 slotted stand as cardholder (3) 1 cardboard, smooth (4.2) 1 cardboard, rough (4.3) 1 metal foil (4.4) 1 metal mirror (4.5) 1 plastic plate used as screen (4.6) 1 synthetic pane (4.7) 1 electric torch (78) 1 mini-darkroom (101)

4.5 Experiment 5 Reflection in a mirror

Sunlight or the light from the torch is reflected in a particular direction when it strikes the tilting mirror. The reflected light can, for example, be directed into the mini-darkroom. A change in the direction of the beam of light enables us to deduce a law about the reflection of light: on a plane mirror the angle of incidence is equal to the angle of deflection. (The angle of incidence is the angle between the incoming beam of light and a line perpendicular to the plane of the mirror.)

Materials: 1 tilting mirror (63) 1 electric torch (78) 1 mini-darkroom (101)

4.6 Experiment 6 Reflections from light and dark surfaces

Insert the card showing human figures in the slotted stand and place both in the mini-darkroom. Then hold the mini-darkroom up to your eyes so that only a small amount of light enters. The lighter areas of the pictures are easier to recognize than the dark ones, because they reflect more light. This means, for instance, that pedestrians can only be seen on unlit streets in a dark night if they wear light coloured clothing.

Materials: 1 slotted stand as cardholder (3) 1 card showing human figures (4.1) 1 mini-darkroom (101)

Magnet and Compass

67

IX. Magnet and Compass

1 Materials contained to carry out experiments for topic “Magnet and Compass”:

1 12468 Test tube, plastic, 100 mm long (12.1)

1 14967 Bar magnet, without mark, 23 mm (12.2)

1 12450 Bar magnet, with red marked north pole (12.3)

1 12620 Knitting needle, 210 mm (16)

1 43142 Plastic box (30.0), containing:

6 12522 Iron screws (30.1)

12 12549 Paper clips (30.2)

10 12514 Nails (30.3)

2 13626 Aluminium rivets (30.4)

1 12590 Wooden disc (30.5)

1 12573 Rubber eraser (30.6)

1 12581 Sheet of copper (30.7)

1 12611 Sheet of iron (30.8)

1 12603 Sheet of cardboard (30.9)

1 12557 Piece of cloth (30.10)

1 12565 Stone (30.11)

1 48185 Sheet of brass (30.12)

1 12485 Spool of thread, 100 m (33)

1 43274 Set of red stick-on dots (42)

2 12638 Compass needles, 35 mm (43)

1 43207 Floating platform for compass needle (44)

4 12646 Brass bearings for compass needle, 0.6 mm dia. (45)

2 2973 Compass cards with pinhole 0.7 mm (50)

1 13057 Compass with pointer lock (hiking compass), 45 mm dia. (51)

2 43282 Mini-waggons for bar magnets (52)

1 43215 Floating platform for bar magnet (53)

1 13111 Filter bowl with lid (61)

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Learning aims specific to the magnet

•Magnetsattract.

•Magnetsexertaforceknownas“magneticforce”.

•Magnetsattractcertainthingsandnotothers.

•Magnetsattractthingsmadeofiron.

•Amagnetmayhavedifferentforms.

•Somemagnetshavemoreforce,othersless.

•Magneticforceisstrongestatthemagnet’sends.

•Magneticforceisexertedoveradistance.

•Magneticforceexertsitselfthroughmanymaterials.

•Likeendsoftwomagnetsrepeleachother.Unlikeendsoftwomagnetsattract each other.

Learning aims specific to the compass

•Thetwomostimportantpartsofacompassarethecompassneedleandcompass card. The card marks the cardinal points of the compass.

•Acompassneedleorientsitselfinanorth-southdirection.Acompasscan be used to find the four regions of the heavens.

•Acompasscanbeusedtoorientamap.

•Acompassneedleismagnetic.Acompassneedleis,therefore,alsoknown as a “magnetic needle”.

•Everymagnethastwopoles(magneticpoles).Theforceofamagnetisgreatest at each pole.

•Everymagnethasanorthandasouthpole.

•Like-namedpolesrepeleachother;unlikeonesattracteachother.

•Compassneedlesmaybepulledoutoftheirnorth/south-seekingposi-tion by another magnet.

•Bystrokingasteelknittingneedlewithamagnet,theneedlebecomesmagnetic. This procedure is referred to as “magnetizing”.


It has been known since the year 585 B.C. (Thales von Milet) that a magnetic force (or magnetism) is exerted between certain ores and materials which are made of iron, nickel, or cobalt. The knowledge that magnetic force can penetrate other materials has been documented in texts dating back to around 80 B.C. (Lucretius, Augustinus approx. 420 A.D.).

In former times magnets were made primarily of iron or steel. Since steel magnets keep their magnetic properties a relatively long time, they are called permanent magnets. Simple (non-alloyed) steels lose their magnetic properties after some time. Therefore, permanent magnets were developed out of different alloys.

There is a magnetic field around every magnet. This field is strongest near the poles. The force diminishes with greater separation from the magnet.

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The magnetic field passes through materials which are not attracted by magnets; i.e. magnets can attract materials out of iron (nickel, cobalt) e.g. passing through air, paper, wood etc.

Magnet’s like poles (north pole – north pole or south pole – south pole) repel each other, unlike poles (north pole – south pole) attract each other (pole law). In the practical application of the magnet as a compass, this pole law is very important.

Already in 841 B.C. a Chinese legend reported on a magnetic compass. Written sources say that the Arabs knew the magnetic compass in the ninth century. In Iceland and France the sea-compass was used in the 12th/13th century. A magnetic stone was attached in the middle of a wooden cross, then this construction was placed on the water and the wooden cross turned in a way that the cardinal points could be read. Around 1300 the magnetic needle was complemented by a compass card. One compass from the year 1451 already showed magnetic declination.

The alignment of the magnetic needle is caused by terrestrial magnetism. The earth is surrounded by a magnetic field which is similar to the one of a bar magnet. The magnetic poles of the earth are identical with the geographi-cal ones. Their positions change somewhat during the course of time. This discrepancy between the compass needle indications and the true North-South direction is called magnetic declination. The geographical location of the place of observation is another factor affecting declination.

Experiments with a freely movable suspended magnetic needle show that it does not find an exact horizontal line, but inclines with its north pole a little downwards (in Europe we call this “inclination”).

The magnetic property (magnetization) can be transferred to materials made of iron, nickel and cobalt. Depending on the materials, magnetism can be retained for a longer or shorter time. It diminishes rapidly, for example, in soft iron following the removal of the magnetic field, although magnetic traces (magnetic remanence) can always be found. In contrast, steel retains magnetism more or less permanently – and becomes a permanent magnet. Strong vibrations and heat can almost destroy magnetism – the material becomes demagnetized.

4 Storage and handling of magnets

One should avoid striking magnets or letting these fall. Magnets are best stored in the test tubes, whereby unlike poles are placed together. Magnets should – where possible – be kept away from other experimental materials containing iron.

Precautions:

- Please approach a magnet with another magnet or articles which con-tain magnetic materials very carefully in order to avoid sudden move-ments or possible squeezing.

- Do not expose metallic tools etc. to magnetic fields.- Use safety goggles! Down falling magnets can splinter. - Persons with cardiac pacemaker should not be exposed to

magnetic fields. - Electronic devices or data medium (e.g. hard disks) must be kept away

from magnetic fields.

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5 Experiments

5.1 Experiment 1 A magnet has a force, we call it the magnetic force.

Lay the nails on a table. Lead the magnet to the nails, the nails are attracted. Magnetic force exerts itself between a magnet and nails.

Materials: 1 bar magnet without mark (12.2) 10 nails (30.3)

5.2 Experiment 2 Some items are attracted by a magnet, some are not.

Lead the magnet to the different items out of the box containing small mate-rials. The magnetic force exerts itself between the magnet and the paper clips, the nails, the iron screws and the sheet of iron. It is not exerted between the magnet and the aluminium rivets, the piece of cloth, the wooden disc, the rubber eraser, the stone and the sheets of cardboard, copper and brass.

Thus, it can only be exerted between the magnet and items which are made of iron or in which iron is contained.

Materials: 1 bar magnet without mark (12.2) 1 box containing small materials (30)

5.3 Experiment 3 Magnetic force exerts itself through many materials.

Hold several materials between the magnet and a nail.

The magnetic force will pass through materials which do not contain iron.

Materials: 1 bar magnet without mark (12.2) or 1 bar magnet with mark (12.3) 1 box containing small materials (30)

5.4 Experiment 4 The poles of a magnet.

Examine which part of the magnet the magnetic force is the strongest. Try to pick up nails with the bar magnet. Most nails remain hanging at the ends of the magnet.

Check the result with a paper clip. Hold it to several sections of the magnet. In the middle there is no attractive force, the paper clip is always pulled to the ends of the magnet.

These ends with the strongest force are called poles.

Materials: 1 bar magnet without mark (12.2) 1 paper clip (30.2) 10 nails (30.3)

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5.5 Experiment 5 The pole rule

Try to bring the two magnets together ends facing each other. Depending on which ends they are facing each other the magnets are attracted (unlike ends/poles) or repelled (like ends/poles). Mark with a red dot also north pole of second magnet. Bring coloured ends (like poles) of the magnets near. They repel each other.

With the help of the test tube you can let the two bar magnets hover above each other when the like poles are facing.

Materials: 1 plastic tube (12.1) 1 bar magnet without mark (12.2) 1 bar magnet with red marked north pole (12.3) 1 red stick-on dot (42)

5.6 Experiment 6 Magnets can attract and repel each other.

A magnet is placed in the mini-waggon. With the second magnet, an at-tempt is made to move the waggon in some direction without touching it. The waggon may be “pulled” or “shoved”, depending on which poles of the magnets are led together.

This exercise can be made more interesting by prescribing a certain road upon which the waggon should be directed.

Note: the operation of keeping the magnets apart when unlike magnetic poles are led together is more difficult than directing the waggon by repul-sion (“shoving”), i.e. leading like ends of the magnets together.

Materials: 1 bar magnet without mark (12.2) 1 bar magnet with red marked north pole (12.3) 2 mini-waggons (52)

5.7 Experiment 7 Constructing a compass.

Pass the point of the brass bearing through the hole of the compass card from the underside. Place the compass needle atop the point of the bearing so that it can rotate freely. Compare this self-constructed compass with the hiking compass. Both compass needles point in the same direction.

Compass needle and compass card are the most important compass parts. The compass card marks the cardinal points i.e. N (North), S (South), E (East), W (West) of the compass and the needle aligns itself with the Earth’s magnetic field indicating the north-south axis of orientation.

Long storage sometimes makes compass needles to indicate wrongly. They no more adjust to the right direction. For renewed magnetizing draw the north pole half of the needle (red point) from the middle over the south pole (non-coloured end) of the bar magnet.

Materials: 1 compass needle (43) 1 brass bearing (45) 1 compass card (50) 1 compass with pointer lock (51)

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5.8 Experiment 8 A compass needle orients itself in a north-south direction.

Turn the compass card under the constructed compass until the red end (the north magnetic pole) of the compass needle is exactly over the “N” (north) point of the card.

We call this procedure “finding north”. After finding north you can also read the other cardinal points E, W, S.

Materials: 1 compass needle (43) 1 brass bearing (45) 1 compass card (50)

5.9 Experiment 9 A freely movable magnet always orients itself in a north-south

direction.

Fill the bowl with water and place the floating platform with the magnet on top into it. The magnet turns into a north-south direction.

Now place the compass card carefully into the water under the floating magnet so that “N” is exactly under the marked pole of the magnet.

Materials: 1 bar magnet with red marked north pole (12.3) 1 compass card (50) 1 floating platform for bar magnet (53) 1 filter bowl without lid (61)


5.10 Experiment 10 Also the compass needle is a magnet.

Construct two compasses. Place the two assembled compasses next to each other, but some distance apart. The magnetic compass needles orient them-selves in a north-south direction.

By moving the compasses closer together, the compass needles turn and touch each other at a marked and unmarked end. Unlike poles attract each other.

Materials: 2 compass needles (43) 2 brass bearings (45) 2 compass cards (50)

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5.11 Experiment 11 A compass needle can be pulled from the north-south seeking

position by a magnet.

The compass card is set to the north-south direction of the compass nee-dle. Lead the south magnetic pole of the bar magnet around the compass points. The north-seeking end of the compass needle and the south pole of the magnet attract each other.

Stand the small bar magnet on end (red marked north pole directed upwards) and lead the compass around the magnet. The south pole (south-seeking end) of the compass needle always points to the upwards directed north pole of the bar magnet.

Materials: 1 bar magnet with red marked north pole (12.3) 1 compass needle (43) 1 brass bearing (45) 1 compass card (50)

5.12 Experiment 12 Magnetization of a knitting needle.

Construct a compass. One pole of the bar magnet is rubbed 15–20 times in the same direction along the length of the knitting needle.

A test is made with the aid of the compass to see if the needle has become magnetized: each end of the knitting needle is led near the north-seeking end, then near the south-seeking end of the compass needle. If only very little attraction or repulsion can be observed, the knitting needle should be turned and held horizontally.

By slowly moving the length of the knitting needle sideways past the north or south end of the compass needle, one can see that the point of the compass needle is, in some places, attracted and at other places, repulsed.

Materials: 1 bar magnet (12.2 or 12.3) 1 knitting needle (16) 1 compass needle (43) 1 brass bearing (45) 1 compass card (50)

5.13 Experiment 13 Knitting needle as compass needle.

Construct a compass. When a magnetized knitting needle as performed in experiment 12 is suspended right in the middle by means of a thread it will turn like a compass needle i.e. it will find the north-south position. Control with compass.

Materials: 1 knitting needle (16) 1 spool of thread (33) 1 compass needle (43) 1 brass bearing (45) 1 compass card (50)

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5.14 Experiment 14 Preparatory exercises for the utilization of a compass.

Place the compass card into the bowl filled with water. Set the compass needle on the floating platform and put both into the water bowl. Now turn the bowl until the north of the compass card corresponds with the marked north pole of the compass needle.

The direction finding by turning the water basin corresponds to turning a compass housing until the “N” of the compass card is under the marked north pole of the compass needle.

Materials: 1 compass needle (43) 1 floating platform for compass needle (44) 1 compass card (50) 1 filter bowl without lid (61)


5.15 Experiment 15 How to use a hiking compass with a map.

Compasses are used to determine a certain direction. The compass card of a hiking compass is much more differentiated than the compass cards used before: the scale is subdivided in angular degrees (starting in the north clockwise from 0° to 360°). The magnetic compass needle aligns itself with the Earth’s magnetic field indicating the north-south direction.

Before using the hiking compass one must at first find “North”. After find-ing “North” one can easily read the cardinal points i.e. N, E, S, W and determine the direction and the corresponding degrees on the scale. The compass housing is turned and the required degrees on the hiking compass are adjusted.

The hiking compass has the great advantage that, after adjustment, the direction remains indicated when one pockets the compass during the hike. Even if one loses sight of the point of destination because of being e.g. in a thick forest the compass can be taken out of the pocket again, the degrees and direction can be read on the adjusted compass and then after loosen-ing the adjustment the North and the exact direction can be found again by turning the compass housing until the north of the magnetic compass needle corresponds again with the north on the compass card.

Sometimes it is necessary to use the compass in combination with a map. Also on the map it is necessary to find North at first. The mode of application for finding North on a map is very comprehensible, if it is considered that every map is representing a large “illustrated compass card”; North is situated on the top of the map, East at the right, South down and West at the left.

Place the compass on the map and turn the map until North of map and North of compass card are identical. Now again the direction can be read on the degree scale of the compass.

As an exercise the pupils try to find and ascertain the cardinal points of their classroom e.g. the windows are facing west .... the wall opposite the blackboard is south etc.

Materials: 1 compass with pointer lock (hiking compass) (51)

Additionally: map

Sound and Tone

75

X. Sound and Tone

1 Materials contained to carry out experiments for topic “Sound and Tone”

1 12468 Test tube, plastic, 100 mm long (12.1)

2 17680 Test tubes, plastic, 152 mm long (14)

1 12620 Knitting needle (16)

1 19500 Stethoscope chest-piece (17)

1 19470 Set of musical bars for “Glockenspiel” (18)

1 19446 Tuning fork (440 Hz) (20)

1 19489 Mallet, plastic (28)

1 12485 Spool of thread (33)

2 19454 Hearing tubes, 630 mm long (35)

1 19497 Flexible strip with oscillation head (36)

4 19462 Ear-pieces for hearing tubes (38)

2 25101 Wooden beads (41)

1 19527 Set of rubber bands (thin) (54) 1 25071 Set of rubber bands (wide) (54)


1 19411 Triangular bridge (70)

1 25110 Spool of string with dog-bone ends (72)

1 19390 Base box with lid and membrane slide (88)

2 25187 Beakers, plastic, with bore (93)

2 19403 Instrument string pegs (96)


By means of simple experiments students can experience

•theinterrelationoflength,tension,andthicknessofinstrumentstringsand their effects upon pitch;

•howsoundcanbeamplified;

•transferofsoundthroughdifferentmediums;

•oscillation,andtheinterdependanceofpitchandoscillationfrequency;

•assemblingofandplayingtunesuponaGlockenspiel;

•thesignificanceofcertaindesigncharacteristicsinseveralmusicalin-struments;

•listeningexercisesthroughtheaidofselfassembledinstruments.

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Sound occurs when objects vibrate. Sound can also occur with the flow of gases or fluids. Sound is transmitted through gases, fluids, or solid masses.

If the flexible strip with oscillation head (36), for example, is held firmly over the edge of a table and the extending section is bent downwards and released – the movement created in the strip is transferred upon the air molecules above the strip in the form of compression of these molecules. They, in turn, pass on this “shove” (and with that, the compression) to neighbouring mol-ecules. At the height of its upward swing, the steel strip swings back in the opposite direction. This creates a low pressure zone on the strips top side (zone of rarefaction), into which the just recently compressed air molecules expand, allowing neighbouring molecules to also expand again.

The same effect, transfer of movement of air molecules, takes place simul-taneously below the steel strip, yet in reverse order. In this way, compres-sion and rarefaction zones of air molecules are created on both sides of the oscillating (vibrating) strip which will, given time, transfer themselves upon yet further neighbouring layers of air.

Sound waves, so created, thus transmit themselves in a similar manner to those waves created by throwing a stone into water. Both types of waves require a medium for their transmission (as opposed to electromagnetic or heat waves). No sound wave can be transmitted, for example, through a vacuum (e.g. outer space).

The transmission velocity of sound in air measures approximately 344 meters per second (758 miles per hour), in freshwater (at 20 °C) 1,450 meters per second (3,240 miles per hour). Its velocity in solids is much greater still – in steel, aluminium and glass, for example – approximately 5,000 meters per second (11,200 miles per hour).

Types of Sounds

The vibrations sent out from any particular material are received by the hu-man ear as either simple or complex musical sounds or as noises, depend-ing on the kind of source producing the sound. A simple musical sound, or tone, is characterized by its simple, periodical vibrations. The faster an object vibrates (i.e. the more oscillations it produces in a second) the higher will be the tone produced. This phenomenon can be easily observed with the help of the steel strip. The shorter the projecting section of steel, the greater the frequency of oscillation and the higher will be the tone.

Musical sound is most often complex – a mixture of several regular, continu-ous tones of different frequencies. There is an easily distinguished fundamen-tal tone to every musical sound, and there may be one or several overtones. These are usually multiple heard less distinctly than the frequency of the fundamental tone. Many sources of sound – especially musical instruments – produce complex musical sounds.

Noise is a mixture of very many tones which are often irregular and non-continuous in character. No single pitch of particular intensity, but rather any range of tones, may predominate. In a rumbling sound (like the rolling of a heavy drum upon a wooden floor or the sound of distant thunder), low-pitched tones predominate, whereas higher, shriller sounds (like the hissing of steam or the squeak of a door hinge) consist mainly of high-pitched tones.

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Musical Instruments and Sources of Sounds

The production of sound by vibrating objects can be seen in the various instruments for music.

In a harmonica as well as in the reed-pipes of an organ, tones are created by the vibration of single, flexible metal reeds of varying lengths which is stimulated by a strong force of air (coming, in the case of an organ, from a pair of bellows).

Vibrating strings create the tones coming from string instruments (guitar, violin, piano) when these are plucked, drawn across or struck with a ham-mer.

Strings (as well as the rubber bands contained in the kit) will vibrate more quickly, the shorter they are or the thinner they are. The strings’ vibrations are carried, in the case of a guitar or violin over the bridge to the sound-board or “table” (in the case of the rubber band, to the base box), so that the entire instrument, and the air molecules contained within, conduct the vibrations of the strings.

The mouthpieces of the woodwind instruments contain single (clarinet, saxophone) or double reeds (oboe, bassoon) which vibrate under the force of air when blown upon.

These vibrations are transferred upon the air column inside a pipe, caus-ing the air itself to vibrate. The longer the instrument (and with that, the air column), the deeper will be the tone created. Hence, pitch can also be altered in a woodwind instrument by the opening and closing of holes in its side (changes in the air column).

With brass instruments, the column of air within the tube is set vibrating by air passing through the vibrating lips of the player.

The air columns of a flute and of an organ’s whistle pipes are set vibrating directly. This type of tone production can be demonstrated by blowing across the top of a test tube. The air passing across the top causes there compres-sion, at first, of the air within the tube. This pressure continues to increase until the trapped air reacts on it in such a way that some air molecules at the top of the tube “escape” with the continually passing air current. When this happens, a zone of rarefaction is created, and neighbouring air molecules from the bottom part of the table rush to fill the low pressure area. By the constant repetition of this cycle of compression and rarefaction, the air column within the tube is set vibrating. These vibrations may be felt when touching the test tube with your fingers.

Intensity (Sound Pressure)

When a vibrating object – such as an instrument string having a constant length and tension – is struck with varying degrees of force, the frequency (and thus the pitch) does not vary, but its intensity does.

Similarly, when we position the flexible steel strip over an edge and cause it to move only slightly, its pendulation (the movement up and down) is only very small and the resulting sound can hardly be heard. The sound becomes easier to hear when the strip is brought to greater pendulation through the use of more force. Hence: the greater the pendulation (amplitude = distance of upward or downward movement from the middle), the louder will be the sound produced.

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An increase of audibility or amplification of a sound can also be achieved by enlarging the sound-conducting surface of a vibrating object. Thus, the sound of a tuning fork may be more easily heard when the end of its stem is set upon a box or table, rather than just being held in one’s hand. The fork passes its vibrations on the larger surface, causing it to vibrate as well. In this way, even more air molecules than before are moved to create sound waves – the intensity becomes greater. This sound amplification is used in the construction of musical instruments.

The Human Ear

When sound waves reach the human ear, the tympanic membrane of the eardrum is set into vibration in accordance with the rhythm of alternating air compressions and rarefactions created by the oscillations of a vibrating object, for example, of the flexible steel strip. In other words: The frequency of vibrations of the eardrum is equal to the frequency of the pendulations of the steel strip when the latter is set in motion.

A normal human ear is only able to perceive such tones having a pitch of between 16 and 20,000 oscillations per sound (16–20,000 Hertz) This range of frequencies is called the audio range. The upper limit depends on a person’s age. Small children may be able to hear tones of 20,000 Hertz (Hz), older people up to 12,000 Hz. Human beings do not perceive sounds outside this audio range.

The lower end of the audio range may be easily demonstrated with the help of the steel strip. When the projecting section pendulates so slowly that its motion may be followed by the eye, we perceive no sound. Any tone or noise can only first be heard above a certain frequency – and not before.

The human ear is able to perceive soft tones as well as loud ones. As a tone fades away, it will, at some point, go below that level of loudness (intensity) under which a human being no longer perceives sounds: The tone falls be-low the threshold of audibility. There is no such threshold towards the other side of the intensity scale, but there is a so-called threshold of feeling. When this level is exceeded by a tone or noise of previously somewhat lesser, yet unpleasant intensity, a feeling of pain is stimulated.

Ultrasonics/Audio Range of Animals

By ultrasonics we mean that range of frequencies surpassing the upper limit of audibility, or greater than 20,000 Hz. Some animals have the ability to also hear frequencies of this greater range. The audio range of a bat lies between 15 and 50,000 Hz.

Noise

When subjected to longer periods of influence and great intensities of noise, our hearing may be permanently damaged. In the most extreme form, noise can even cause death. Noise, therefore, can be understood as damaging, annoying and undesired sound.

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The effects of noise manifest themselves in

•hearingimpairments,sleepingdisordersandaccompanyingnegativeeffects on health.

•disturbancesinconversationorin,saytheenjoymentofmusicand

•interruptionsofamentalactivity.

In order to reduce the damaging effects of noise, its sources – particularly machines like air hammers, pile drivers, etc. – are provided with covers of sound-dampening (and sound-absorbing) materials (e.g. porous materials like felt, foam rubber and others). Hearing protection devices, like ear-flaps or ear-plugs, may also be used to guard against ill-effects of noise.

4 Experiments

4.1 Experiment 1 No sound without vibration

Hold the flexible steel strip over the edge of a table. Bend the extended section downwards and release it. It vibrates upon letting it go. Repeat this procedure with the knitting needle. The base box may be used to better stabilize the flexible steel strip (or knitting needle). Appropriate recesses for this are provided on the bottom of the box. Press the box down firmly to prevent it from moving, and keep it flush with the edge of the table.

A sound can only be heard when the strip is in a state of vibration. Compare the sounds arising from the steel strip and the knitting needle. An observa-tion of the vibrations (high tones) shows that they occur too rapidly for their motion to be followed by the eye any longer. If the strip is vibrating slowly, so that the to-and-fro motions are easily detectable and almost countable, no sound will be heard.

Materials: 1 knitting needle (16) 1 flexible steel strip (36) 1 base box (88)

4.2 Experiment 2 Vibrations can be made visible by immersing a vibrating tuning

fork in water

Fill the filter bowl with water. Strike the tuning fork on the table and place the vibrating fork near the surface of the water. Vibrations are visible by the circles on the surface of the water.

Materials: 1 tuning fork (20) 1 filter bowl, without lid (61)

Additionally: water

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4.3 Experiment 3 Vibrations of a tuning fork can be made visible also with the aid

of a thread with a wooden bead

A tuning fork is placed in one of the two smallest holes on top of the base box and struck with the mallet, and a thread with a wooden bead hanging from it is held near a prong of the tuning fork. The bead is always repelled after making contact with the vibrating tuning fork.

Materials: 1 tuning fork (20) 1 mallet (28) 1 spool of thread (33) 1 wooden bead (41) 1 base box (88)

4.4 Experiment 4 High and low tones

Loop a thin and wide rubber band underneath each of the hooks of the base box. Pull them over to the opposite end, around the slits of the pegs. If the pegs are lifted slightly they can be turned and locked inplace to a new position (see illustrations).

Since only one “string” of each of the rubber bands is necessary for the experiments, one part of the rubber bands should be stretched below the triangular bridge. The bridge can be moved to alter the “length” of the string (rubber band) being played.

The shorter the string, the higher the tone will be. Wide strings produce lower tones than do thin ones – provided that the lengths are equal. This property can also be proven with the help of the base box, by stretching two rubber bands of different thicknesses next to each other. The question of relationship between the length of the sound producer and resulting pitch of tone can be concretely answered once more with the aid of the knitting needle by trying to elicit higher and lower tones from it.

When there is too much noise in the classroom, the hearing tubes can be slid over the projections provided on the side of the base box, in order to be able to hear the produced sounds loud and clear, without outside disturbance. An earpiece should be fitted over the other end of each tube by twisting and then placed firmly into the ear. The tube should continue to be held in place firmly, too, to prevent its slipping out. After use the earpieces should be cleaned by rinsing in hot water.

Materials: 1 knitting needle (16) 2 hearing tubes (35) 2 earpieces (38) 1 thin rubber band (54) 1 wide rubber band (54) 1 triangular bridge (70) 1 base box (88) 2 instrument pegs (96)

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4.5 Experiment 5 Putting together a glockenspiel

Stretch two rubber bands lengthwise around the base box as shown on illustration so that the metal bars can rest freely on top of them. The bars should be arranged to produce an ascending scale. When the musical bars are struck with the mallet, they vibrate and tones are created. The previously gained knowledge about relationships between the size of a sound producer and the pitch of tone created can be applied here.

Materials: 1 set of musical bars (18) 1 mallet (28) 2 thin rubber bands (54) 1 base box (88)

4.6 Experiment 6 Air produces sounds and tones

Remove the lid of the base box by pushing upwards only one side at a time and place the three test tubes into the lid. Blow into the test tubes and try to produce tones. The mouth of each test tube should not be brought directly in front of the lips while “blowing”, but instead be held below them in order to better direct the air into the test tube, which has to be driven by protru-sion of the upper lip. Again it is shown that the smaller sound producer (the shorter test tube) gives a higher tone than the longer test tubes.

Using the instruments string peg as a whistle the produced tone is high and shrill (a small sound producer). Here, however the hollow post of the string peg must be placed against the lips to blow.

Materials: 1 test tube (12.1) 2 test tubes (14) 1 base box (88) 1 instrument string peg (96)

4.7 Experiment 7 Sound amplification with the aid of a conducting surface;

sound absorption

A tuning fork cannot be heard if it is struck with the mallet while being held in the hand. If the tuning fork is placed, however, into the small hole on top of the base box a tone can be heard which means sounds are louder (amplified) upon a conducting surface (base box).

Stretch the rubber bands across the base box using the pegs and bridge and remove the lid to find out whether the body of the box has an amplifying effect. While being held in hand the rubber “instrument strings” can hardly be heard. The tone can be amplified again by pressing the lid against a table top or set back on the box. Both possibilities produce approximately the same amplification which means the important factor for sound amplifica-tion is solely the enlargement of the conducting surface.

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Not every surface of object is suited to amplifying sound. With a sponge, placed under the base box, for example, no amplification of the tones com-ing from the base box can be effected. No amplification occurs, either, when the sponge is laid between the music box and table top or it is held up to an ear and the vibrating tuning fork against the opposite end. The sound is absorbed.

Materials: 1 tuning fork (20) 1 mallet (28) 2 rubber bands (54) 1 triangular bridge (70) 1 base box (88) 2 instrument string pegs (96)

Additionally: sponge

4.8 Experiment 8 Sound amplification by direct conduction (stethoscope)

Take the stethoscope chest-piece apart to show that it is made up of merely a flexible membrane and a cone-shaped flat tunnel with two ends, to which the hearing tubes are to be connected. Assemble the instrument using also the earpieces. In a stethoscope, sound e.g. heartbeat is conducted more or less directly to the air inside the hearing tubes and from there to the ears without allowing the sound – as would be otherwise the case – to disperse and in so doing, be weakened.

The stethoscope should be pressed as close to the skin as possible since clothes weaken the conduction of sound. Small animals make particularly good subjects for experimentation.

Practical suggestion: The hearing tubes fit very tightly around the metal ends of the stethoscope chest-piece. It is not necessary to slip them on further than the first ring. In removing, pull the hearing tubes slowly off the metal ends of the stethoscope chest-piece. To ease sliding and to avoid a stretch-ing of the hearing tubes sometimes it might be necessary to push the tubes off the metal ends with the fingernails.

Materials: 1 stethoscope chest-piece (17) 2 hearing tubes (35) 2 earpieces (38)

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4.9 Experiment 9 Sound conduction by means of a string

Unroll the spool of string and slip one dog-bone end through the hole of the membrane slide of the side edge of the base box.

Insert the other end through the bore of the beaker. One student holds the beaker against his ear, while the other inserts a tuning fork in the lid of the sound box at the opposite end of the tightly drawn string. Then the tuning fork is tapped with the mallet. Even over this large distance, the sound of the vibrating fork can be easily heard – without the string an impossibility.

Similar attempts may be made, too, with the rubber bands and with a watch, pressed firmly against the base box.

Practical suggestion: In pulling the string tight, the dog-bone ends are pulled against the insides of the membrane slide and the beaker, such that a solid connection between the string, the base box and the beaker is main-tained. Care must be taken that the string does not come against wall cor-ners, door frames or other persons; it must be held taut and free to be able to “vibrate”. In order to facilitate removal of dog-bone ends from the base box, the lid section may be clapped open from the side and the dog-bone end slipped back through the hole of the membrane slide.

Materials: 1 tuning fork (20) 1 mallet (28) 1 spool of string (72) 1 base box (88) 1 beaker with bore (93)

4.10 Experiment 10 String telephone

The dog-bone ends are inserted through the bores in each beaker. Pull the string tight. One student holds a beaker against his ear, the other speaks softly into the other beaker. The size of the beakers is suited exactly over an ear in order to block out any foreign noises.

Materials: 1 spool of string (72) 2 beakers with bore (93)

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XI. Water Purification

Materials contained to carry out experiments for topic “Water Purification”

1 17613 Triple magnifier (11)

1 13197 Metal spoon (25)

1 13200 Connecting tube, transparent, 300 mm (31)

1 17710 Set of double dishes (55)



2 13138 Filter tubes (68)

2 13146 Copper wire gauzes (75)

1 13154 Strainer for filter tube (76)

2 13120 Push-on connectors for filter tubes (77)

1 12913 Food colouring (90)

1 12794 Plastic beaker, 100 ml, graduated (92)


The entire world of living things depends upon water. Life itself would not be possible without this natural resource.

The students learn to recognize water in its different states during their very early primary school years, and rapidly relate water in the environment to plant and animal life.

By means of simple experiments students develop an understanding and appreciation of the earth as a natural water purification plant.

Answers are given to the following questions:

•Whichtypeofsoilletswaterpassthroughmostrapidly?

•Howdoesgroundwatergetclean?

•Whatdoesandwhatdoesnotgetfilteredoutbythesoil?

•Howdosewershelpkeepourwatersupplyclean?

•Whyarewatertowersoftenlocatedonahill?

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Obtaining drinking water from ground water and surface water

Ground water is particularly suitable as a source of drinking water due to its specific chemical, physical, and bacteriological properties. It is largely bacte-ria-free, odourless, clear, colourless, and remains at a constant temperature. A certain proportion of dissolved salts also contributes to the (more or less) good taste of drinking water.

Ground water is formed when rain water and river water sink into the ground in a natural process. It fills up cavities in loose layers of earth and rocks. Ground water can only be found in permeable layers of earth. Beneath those layers are water-impermeable layers. Layers of rock, sand and gravel are permeable, whereas clay forms an impermeable layer. The volume of ground water is determined by precipitation levels, evaporation, the plant cover, the terrain, and the permeability of earth layers. Because the quality and supply of ground water differ greatly from region to region and the demand of drinking water is rising constantly, we must increasingly move towards artificial ground water enrichment and processing of surface water.

In earlier times epidemics were caused by drinking water contamination. Due to ignorance of the dangers involved, no countermeasures were taken. Today water supplies are often protected by special measures such as water sanctuaries, cordoning off wells, etc. In addition, all public water works are subject to constant supervision through water sampling and analysis.

Water is obtained from ground water reserves by drilling deep holes until reaching the bottom of the aquifer. Wells are installed and the ground water is brought to the water works by means of pumps, where it is processed for drinking.

Drinking water is derived from surface water by filtering river water, for example, through fine and coarse screens, pumped to reservoirs and into the water works, and processed until it reaches the quality required for drinking water.

Drinking water in pure water reservoirs at the water works is supplied to consumers by means of pumps and water towers.

4 Experiments

4.1 Experiment 1 Which type of soil lets water pass through most rapidly?

Objectives:

•Toseethatwateriseitherheldinthesoilorpassesthroughit,depend-ing upon the type of soil.

•Toseethatgravitymovesgroundwaterthroughrockstothelowestlevel.

•Tounderstandthatthesmallertheparticlesofsoil,thegreatertheabil-ity to slow down water movement.

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Sand

Gravel

Let students collect some soil types such as sand, gravel, topsoil, humus or clay. This could be a homework assignment given some days before this experiment is made.

Put the lid on the filter bowl. Slide the red push-on connector into the lid. Place the filter tube (cone-shaped end down) into the connector. Slip the copper wire gauze into the filter tube.

Collect the first soil sample with the beaker. Use the spoon to transfer the soil from the beaker into the filtering system.

Clean the beaker and fill it with water. Pour the water into the filter tube. Determine the time it takes for the water to pass through the first type and record the result.

Clean filter tube and bowl taking care not to throw the copper wire gauze out with the soil sample.

Note: Soils should not be washed out down the sink.

Repeat above experiment with remaining types of soil.

Materials: 1 spoon (25) 1 filter bowl with lid (61) 1 filter tube (68) 1 copper wire gauze (75) 1 push-on connector (77) 1 beaker (92)

Additionally: water, different types of soil e.g. sand, gravel, topsoil

4.2 Experiment 2 How does ground water get clean?

Objectives:

•Toseethatrocks,dependingupontheamount,sizeandarrangementof the pore space, vary in their ability to absorb and clean water.

•Torealizewhysandisthebesttypeofsoilforfiltrationanddrainage.

•Tounderstandthatgroundwaterisoneofourmostimportantnaturalresources.

Use soil types from experiment 1, however, please note that water will filter through more rapidly if the soil is already wet.

Discuss the criteria for a good filtration or drainage column. For example, gravel and sand or topsoil and gravel may be types of soil which resemble soil found in your area.

Build a filtering system using each two filter tubes, connectors and wire gauzes. Fill the filter tubes with types of soil. Pour water into the top filter tube. Determine the filtration time.

Repeat with remaining types of soil and include one experiment using sand in both filter tubes. Record and discuss the results.

Because sand does not contain materials which are leached out by water it is a good filtering material. To take advantage of this ability reservoirs are very often located near drainage areas containing sandy soils.

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Topsoil

Gravel

If there is enough time let the water in the filter bowl undisturbed for one hour and record how clear the filtered water appears.

Materials: 1 spoon (25) 1 filter bowl with lid (61) 2 filter tubes (68) 2 copper wire gauzes (75) 2 push-on connectors (77) 1 beaker (92)

Additionally: water, different types of soil e.g. sand, gravel, topsoil

4.3 Experiment 3 What does and what does not get filtered out by the soil?

Objectives:

•Toseethatgroundwaterissubjecttoalltypesofenvironmentalpollut-ants.

•Toseewhyoilspillsonlandcanworktheirwayintothewatersupply.

•Tounderstandthatoilcoatssoilparticlesandcanaffectthefiltrationability of soil.

•Tolearnthatoilcannotbecompletelyremovedfromsoil.

Build a filtering system using the filter bowl with lid and each two filter tubes, connectors and wire gauzes. Fill the filter tubes with types of soil as described in experiment 1. Mix water with chalk dust together in the beaker. Pour this mixture into the top filter tube and allow it to drain through. Record the time it took and compare with the results of experiment 2. Collect the filtrate and examine it. Record results.

Repeat this experiment with food colouring, then with vegetable oil. The experiment with oil should be in the last sequence of experiments since oil binds soil and cannot be separated from it. Nevertheless after this last experiment there will be some oil still visible on top of the water.

Ask the students to suggest ways to retrieve materials from the water. Among the suggestions perlite (binding agent) might be mentioned which removes oil from the water by absorption.

To test the soil to see if oil remains rub some soil onto a piece of paper or paper toweling. A translucent stain will remain if oil is present. Students will realize that the oil cannot be completely removed from the soil.

After the experiments are completed, the filtering system should be emptied and cleaned immediately. Please note oil and soil types should not be put into a sewage system. Both should be disposed of in a waste bin.

Materials: 1 spoon (25) 1 filter bowl with lid (61) 2 filter tubes (68) 2 copper wire gauzes (75) 2 push-on connectors (77) 1 beaker (92)

Additionally: water, chalk dust, food colouring, vegetable oil, different types of soil e.g. sand, gravel, topsoil

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4.4 Experiment 4 How do sewers help to keep our water supply clean?

Objectives:

•Torealizethatconservationofgroundwaterisaworldproblem.

•Torealizethatgroundwaterisaveryimportantnaturalresource.

Let the students collect materials which will simulate waste water running into sewers from city or country streets. Construct a filtering system, as was done in experiment 1. Place the plastic strainer in the filter tube. Mix the different types of materials (small, large, soluble, insoluble) with water in the beaker. Be sure that the beaker is almost full.

Pour the beaker contents into the filter tube. Put a piece of white paper be-hind the bowl and check the liquid by looking through the bowl from the other side. Allow the liquid to settle for ten minutes. Then check the clarity and the amount of sediment again. Record the results.

Materials: 1 spoon (25) 1 filter bowl with lid (61) 1 filter tube (68) 1 copper wire gauze (75) 1 strainer (76) 1 push-on connector (77) 1 beaker (92)

Additionally: water, materials such as broken twigs, cotton, shredded paper, sand, chalk dust, detergent, vegetable oil

4.5 Experiment 5 Why are water towers often located on a hill?

Objectives:

•Todemonstratetheprinciplethatliquidsseektheleveloftheirsource,often expressed as “water seeking its own level”.

Please perform this experiment in a waterproof area since splashes and spills may occur and take care that the fine powder of the food colouring is not blown around since it will temporarily discolour fabrics and skin.

Connect two filter tubes at their bases with the connecting hose. Sprinkle two to three grains of the food colouring into the beaker containing water. If necessary stir with spoon until the food colouring is dissolved. Pour the coloured water into one filter tube holding both in an upright position. Change the position of the filter tubes and notice that the water levels inside the filter tubes immediately readjust to keep the levels constant.

Liquids that are in open containers and connected to each other rise to the same level in each of the connected containers.

In a water supply station, water is kept very often in a tank high on a hill. The water will flow, due to gravity, to the houses and places at a lower level and come out the water tap.

Materials: 1 connecting tube (31) 2 filter tubes (68) 1 food colouring (90) 1 beaker (92)

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Seeds and water with detergent

Seeds and water with salt

Seeds and water oil

Seeds and plain tap water

4.6 Experiment 6 How does polluted water affect seeds and plants?

Objectives:

•Tolearnthatseedgerminationisaffectedbyenvironmentalconditions.

•Tolearnthatplanthealth,growth,anddevelopmentareaffectedbychemicals in the water.

•Toobserveseedstructuresdevelopintoyoungplantsthatarenourishedby the food stored in the seed.

Materials such as detergent, oil, salt, vinegar and sugar will be the pollutants. They must be dilluted so that they do not immediately destroy the seeds. Mix about ½ spoon of a pollutant in about 200 millilitres of water and stir to mix or dissolve. The polluted water can be covered with plastic wrap and kept for the duration of the experiment.

Use a magnifying glass for observing the seeds and small plants.

As a standard some seeds should be watered with plain tap water for compari-sons with the watering with polluted water. Only quick-germinating seeds such as beans or peas should be taken for this experiment. Use containers like e.g. filter bowl, multi-purpose container and set of double dishes.

Label the underside of these containers. The labels should mention which pollutant was used. Spread small pieces of cotton across the bottoms of the containers and moisten the cotton with one or two spoons of the polluted water. Place 3 or 4 seeds on top of the moistened material. Cover the contain-ers with plastic wrap to keep the moisture in and to decrease the chances of contamination by bacteria. If necessary moisten again in the next days.

Carefully examine and even measure the seeds watered with polluted water and compare with seeds watered with plain tap water. Record the results.

Materials: 1 triple magnifier (11) 1 metal spoon (25) 1 set of double dishes (55) 1 multi-purpose container (60.1) 1 filter bowl (61)

Additionally: containers with polluted water, labels, pieces of cotton, plastic wrap

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XII. Wind and Weather

1 Materials contained to carry out lessons for topic “Wind and Weather”

1 13839 Metal mirror (4.5)



1 13057 Compass with pointer lock (hiking compass), 45 mm dia. (51)



1 13693 Tilting mirror (63)

1 13014 Graduated measure for collecting rain (79)


•Thestudentsaremadeawareofrandomexperiencesrelatedtothesubject “weather” which occur in their environment.

•Thestudentscandescribeweatherconditionsineverydaylanguageandlearn about the four specified weather elements, temperature, clouds, precipitation, wind strength.

•Thestudentslearnhowtoreadmeasuringinstrumentsandenterthereadings in tables and temperature curves.


All weather phenomena can be attributed to temperature, atmospheric pressure and atmospheric humidity.

Atmospheric pressure and humidity cannot usually be directly observed; they are however the cause of clouds, wind and precipitation, i.e. weather conditions with which students are already familiar and which they can observe.

Temperature

Temperature measurement makes use of most substances which expand when heated, and contract when cooled. The most common measuring instrument is the liquid thermometer, filled with alcohol or mercury.

The graduation of a thermometer is in principle arbitrary. With the exception of a few Anglo-Saxon countries, the Celsius scale is the most commonly used scale today, determining the freezing point of water at 0 °C and the boiling point at 100 °C.

Particular care must be taken when measuring the temperature to ensure that the thermometer is protected from sunlight and water (due to the lowering of temperature during evaporation). Also, the thermometer cannot be located too close to the ground since various types of land can heat up and cool at

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different rates. The official meteorological stations record the temperature 2 m above the ground in a thermometer hutch located on a grass surface at a minimum distance of 10 m from other buildings.

Extreme temperatures which have been observed on the surface of the Earth range from 58 °C (Sahara) to –88 °C (Antarctic). The highest and lowest tem-peratures recorded in Central Europe are 44 °C and –39 °C respectively.

Wind

Wind always occurs as the result of pressure differences in the atmos-phere. Atmospheric pressure differences normally occur under the influence of temperature. For example, land heats up faster than water at the same degree of thermal irradiation. The layers of air above land and water heat up at different rates, resulting in differences in atmospheric pressure. The wind ensures pressure equalization in the atmosphere.

Wind recordings measure the strength and direction of the wind. These recordings must not be carried out directly above the ground since the wind direction and particularly the wind strength are affected by friction on the ground. Also large buildings, hills etc. locally deflect the movement of air from its original direction, or vary its speed. For this reason, wind direction and strength are recorded internationally in open spaces at a height of 10 m above ground level. At a height of 4 m, for example, a wind speed of about 20 % less than at a height of 10 m can be expected, while at 30 m the wind speed increases by approx. 20 %.

The direction of the wind is specified by the point of the compass from which it blows. For example, a western wind blows from west to east.

In order to obtain comparable data with regard to wind strength, as early as 1805 Admiral Sir Francis Beaufort compiled a table which differentiates twelve different wind strengths in accordance with their effect on land and at sea. The use of this “Beaufort scale” table can of course provide only an estimate of the wind strength.

Today, anemometers are normally used (the Greek word “anemos” = "wind”). They enable precise recording of the wind strength.

Anemometers actually measure the wind speed. However, the scale can also be calibrated to the Beaufort scale since the strength of the wind de-pends only on its speed. The wind strength according to the Beaufort scale and the corresponding speed ranges are listed in the table on the master copy on page 99.

Clouds and precipitation

Since warm air can absorb more water vapour than cool air, when warm air cools, part of the water vapour contained in it condenses to form extremely fine droplets of water. These fine droplets which form mist or a cloud can remain suspended in the air since they are extremely light and held by ascending currents of air. However, if several of these fine drops combine to form drops of increasing size, they become so heavy that they fall to the ground in the form of rain. On the other hand, if these drops of water are quickly carried high up by a strong current, as is often the case in thunder clouds, the drops of water freeze and then fall to the ground in the form of frozen pellets. If, as the result of repeated upward turbulences in the thunder cloud, further ice is formed around the pellets, they are called hailstones.

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Hailstones can reach a considerable size, however, during their fall through warmer layers of air, they often melt again before they reach the ground. This then results in large raindrops which often occur at the beginning of a thunderstorm. When atmospheric humidity condenses at temperatures below 0 °C, fine ice crystals are formed which in most cases grow together to form snowflakes.

The amount of cloudiness is specified in quarters of the sky: clear, quarter cloud (fair), half cloud, three-quarter cloud (cloudy), overcast.

Also, the amount of precipitation which reaches the ground is measured and recorded daily by meteorologists. The rainfall level is determined with the rain gauge. The amount of rainfall can be calculated from the rainfall level.

The rainfall level indicates the amount of rain or water resulting from melted snow, hail, etc. on even ground if no water could escape, seep into the ground or evaporate. The rainfall level is measured in mm, the quantity of rainfall is calculated in litres per m2 (l/m2).

A rainfall level of 1 mm therefore means that every square millimetre (mm2 ) of the ground’s surface carries a cubic millimetre (mm3) of rain-water.

1 m2 = 1,000,000 mm2. One square meter therefore carries 1,000,000 mm3 of rainfall i.e. 1,000 cm3 or 1 litre. The level of 1 mm therefore corresponds to the quantity of rainfall of 1 l/m2.

The numerical values of the rainfall level (in mm) and quantity of rainfall (in l/m2) are identical. If we now consider small or large surfaces, then the amount of rainfall is correspondingly small or large; however, the rainfall level is 1 mm regardless of the size of the surface. Generally, the rainfall level can therefore be measured with a cylindrical vessel which has a millimetre scale.

Care must be taken to ensure that splashwater cannot fall into the meas-uring device along with the rain. For this reason the rain gauge in weather stations is installed at a level of approx. 1 m above the ground. To ensure the rainfall level is not adversely affected by the environment, the rain gauge should be installed away from immediate obstructions (buildings, trees) in such a way that the minimum distance is equal to their height.

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clear half cloud

overcastthree-quarter cloud (cloudy)

quarter cloud (fair)

8 20

4 Weather chart symbols

The data observed by the individual meteorological stations with regard to temperature, clouds, wind and rainfall are entered on the weather chart in order to obtain an overview of the weather situation for a large area.

Well-known symbols are found in:

•thevariousweatherchartsprovidedbytelevisionandnewspapers,withtheir familiar, graphic means of representation;

•theofficialweatherchartswhichusedefinite,internationallyused symbols.

The following internationally recognized symbols are used in the weather reports printed in newspapers:

The degree of cloudiness is indicated by the corresponding black segments of a circle. A distinction is made between:

Precipitation is indicated by a symbol next to the circle.

Examples

Temperature: 8 °C 20 °C

Wind speed: 45 km/h 0 km/h

Wind strength: 6 0

Wind direction: NW wind –

Cloudiness: three-quarter cloud clear

Precipitation: rain –

On the weather chart, meteorologists connect stations with the same at-mospheric pressure with a line called the isobar; atmospheric pressure is written on this line. The isobars indicate the location of areas of high and low pressure.

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5 Lesson Suggestions

5.1 Lesson suggestion 1 What makes the Weather?

Learning Objectives

•Temperature,clouds,windandprecipitationareimportantweatherele-ments.

•Thestudentscandescribeweatherconditionsineverydaylanguageandlearn about the four specified weather elements.

Suggested Procedure

The four weather elements were selected from the complex phenomenon of “weather” since they can directly be observed by students. Due to their abstract nature, atmospheric humidity and atmospheric pressure are not discussed here although they are of great significance to weather and par-ticularly to weather forecasting.

Using everyday language, the students should try to express their observa-tions as clearly as possible. The teacher should attempt to guide them in providing accurate descriptions. Instead of the current weather, the students can also describe weather occurring in other seasons. The descriptions are first written on the blackboard in random order. By underlining in different colours (comments on temperature red, clouds blue etc.), the four important elements can then be pointed out and named.

The terms “clouds” and “rainfall” must be introduced. For example, children do not always immediately refer to clouds – the question as to why the sun cannot be seen on some days draws the attention of the students to the fact that clouds mask our view of it. The students are aware of precipitation only in the concrete forms such as rain and snow, occasionally hail, perhaps also dew. These phenomena occur as the result of precipitation of the moisture (water vapour) in the atmosphere during cooling, similar to the way water vapour contained in breath condenses on a cold window or a mirror.

After the students have acquired a general sense of the four weather ele-ments, these are discussed individually in the following.

5.2 Lesson suggestion 2 Recording the Temperature

Learning Objectives

•Thestudentscancorrectlymeasuretheairtemperatureandrecordthefindings.

Suggested Procedure

The aim is learning to use a thermometer. The students should be instructed in the proper manner to handle a thermometer and how to avoid measuring errors. Recording temperature can be practised for example by measuring the air temperature inside and outside the classroom and also with the aid of containers filled with water at different temperatures.

Reading temperatures above and below freezing point i.e. +3 °C and –3 °C requires special attention. The terms “plus” and “minus” can be initially in-troduced with the signs “+” and “–”. At a later stage in the learning process,

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For the weather observation table for two weeks see page 100

See temperature table for one week on page 99

steps should be taken, to omit the “+” for temperatures above 0 °C. The findings are entered in a table.

Materials: 1 thermometer, –3 °C to +103 °C (6) 1 thermometer, –25 °C to +50 °C (7) 1 multi-purpose container (60.1) 1 filter bowl (61)

5.3 Lesson suggestion 3 Measuring the Temperature Day by Day

Learning Objectives

•Weatherobservationsoveralongperiodoftimecanbeusedincom-parison only when it is carried out daily at the same place and time. The air temperature is recorded outdoors in a shady place which is at least 0.5 m above the ground.

•Thestudentsenterthetemperaturereadingsinatableandlatercom-pile the figures to form a temperature curve.

Suggested Procedure

Before daily recordings of the temperature can begin, a class discussion can be held as to where and when recordings should take place. As a result, the students should remember the following precautions:

Air temperature is recorded

•outdoors

•inashadyplace

•atleast0.5maboveground

•everydayatthesametime

Noting the measured Figures

The student responsible for recording goes to the measuring place, reads the measured figures and writes them down. All students enter the measured temperature either in their note books or in their copy of the temperature table (see page 99). At first the temperature in °C is indicated over the thermometer of the respective day. Then temperature is marked on the thermometer scale by a cross line.

At the end of the week, the recording symbols are joined together with a straight line, resulting in a temperature curve. The students describe on which days the lowest and highest temperatures were attained.

The students can be prompted to provide comments on the progression of temperature during the week by answering the following questions:

•Didthetemperatureincrease,droporremainunchangedduringthecourseoftheweek?

•Werechangesgradualorsudden?

•Onwhichdaywasitwarmestmeasuringtime,andwhichdaycoldest?

Even after the first week, the daily temperature recordings are pursued. These measured values are entered in the weather observation table for 14 days.

Materials: 1 thermometer, –25 °C to +50 °C (7) copies of the temperature table on page 99 and the weather observation table on page 100

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5.4 Lesson suggestion 4 Clouds

Learning Objectives

•Thedegreeofcloudinessisindicatedbythecorrespondingblackseg-ments of a circle. A distinction is made between

clear,

quarter cloud (fair),

half cloud,

three-quarter cloud (cloudy),

overcast.

The students can determine the degree of cloudiness by observing the sky, however, the different types of clouds are not discussed.

Suggested Procedure

Estimating the amount of clouds is not a simple task. One should imagine pushing the clouds together in the sky and estimate how many quarters of the sky are covered. The estimate of various students will often not coincide. In these cases, after observing the sky once again, a consensus should be reached. The students enter the findings in words and in the corresponding cloud symbol in their notebooks or in the table for fourteen days.

5.5 Lesson suggestion 5 Wind Direction

Learning Objectives

•Thestudentslearnthepointsofthecompass,N,S,E,W,NE,NW,SE,SW and their representation on a compass card.

•Thewindisidentifiedaccordingtothepointofthecompassfromwhichit blows.

Suggested Procedure

The wind direction can be determined for example by the direction in which the clouds move across the sky. Using the compass, the north is determined, then the mirrors are placed next to the compass if possible on table level. In the mirrors the clouds can be observed moving from a certain direction which can be read from the compass.

On some days, however, the direction of movement of the clouds may not be observed in the mirror very clearly also there might be no clouds at all. In these cases the teacher may wet one of his fingers and hold it upright to find the direction of the wind.

The findings are recorded in the notebooks or in the weather table.

Materials: 1 metal mirror (4.5) 1 compass with pointer lock (51) 1 tilting mirror (63) copies of the weather observation table on page 99

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For the weather observation table for two weeks see page 100

5.6 Lesson suggestion 6 Recording the Rainfall

Learning Objectives

•Thestudentslearnthedifferenttypesofprecipitation:rain,snow,anddew, as well as their corresponding symbols.

•Themeasuringlocationforrainfallshouldbeatareasonabledistancefrom buildings, trees and the ground.

•Thestudentslearnhowtomeasurethelevelofrainfallwiththeaidofarain gauge.

Suggested Procedure

For students precipitation is an important weather phenomenon, sometimes even used as a synonym for “weather”.

Weather observation centres on the type and quantity of precipitation, there-fore equal importance should be attached to these weather factors as it is to temperature, clouds and wind direction.

Types of precipitation

It becomes obvious to the students that symbols must be used in order to represent the types of precipitation on the weather chart. During a class discussion, the students name the different types of precipitation which they know and develop their own corresponding symbols. These symbols can be used in the weather survey. Initially, the symbols can be restricted to those for rain, snow and dew, and the others can be subsequently introduced as needed (the term “snow” should not be used but rather “snowfall” so that the students do not enter in the weather table snow which is already on the ground). In the case of a thundershower, the symbol for rain should be entered in the weather table in addition to the symbol for thunder. The students’ symbols will probably differ very little from the pictograms used in the official weather charts. It is therefore an easy transition to use the of-ficial symbols.

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Quantity of Precipitation

In order to convey the students that it is not sufficient in the weather survey to simply indicate the type of precipitation, the teacher could, for example, remind them that during a rain shower, the ground could become only slightly wet while after a long period of rain, large puddles or even flooding can occur. The students will then realize that the quantity of precipitation is also decisive and must be recorded. Generally, any container with a mil-limetre scale can be used to read the rainfall level.

The teacher should explain that rain gauges should not be placed on the ground since additional water could splash into the gauges.

The place where the rain gauge should be installed is determined before daily recordings start. If possible the rain gauge should be placed 1 m above the ground and far away from the nearest obstacles (houses, trees).

The findings are recorded in notebooks or in the weather table.

Materials: 1 graduated measure as rain gauge (79) copies of the weather observation table on page 99

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99Worksheet © Cornelsen Experimenta

0 °C

above 0 °C (+, plus)

below 0 °C (–, minus)

Temperature table for one week

Place of measuring: Time of measuring: a.m./p.m.

Temperature

Day of the week Date

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100100 Worksheet © Cornelsen Experimenta

Symbols

Weather observation table for two weeks

Precipitation Type Level in mm

Wind direction Wind strength

Cloudiness

Day of the week Date

Temperature

°C

Wind strength

Calm

Light breeze

Moderate breeze

Strong breeze

Gale

Storm

Cloudiness

Clear

Quarter cloud (fair)

Half cloud

Three-quarter cloud (cloudy)

Overcast

Precipitation

Rain

Snow

Drizzle

Hail

Pellet hail

Dew

Hoarfrost

Fog

Thunderstorm

Shower

Wind and Weather

101Worksheet © Cornelsen Experimenta

Cloudiness

Clear

Quarter cloud (fair)

Half cloud

Three-quarter cloud (cloudy)

Overcast

Precipitation

Rain

Snow

Drizzle

Hail

Pellet hail

Dew

Hoarfrost

Fog

The addition of this symbol signifies “shower”, i.e.:

Rain shower

Thunderstorm

Meteorological weather symbols

Symbol Force Description Speed in km/h

Specifications (for use on land)

0 Calm 0 Calm; smoke rises vertically

1 Light air 1–5 Direction of wind shown by smoke drift, but not by wind vanes

2 Light Breeze 6–11 Wind felt on face; leaves rustle; ordinary vanes moved by wind

3 Gentle Breeze 12–19 Leaves and small twigs in constant motion; wind extends light flag

4 Moderate Breeze 20–28 Raises dust and loose paper; small branches are moved

5 Fresh Breeze 29–38 Small trees in leaf begin to sway; crested wavelets form on inland waters

6 Strong Breeze 39–49 Large branches in motion; whistling in wires; umbrel-las used with difficulty

7 Near Gale 50–61 Whole trees in motion; inconvenience felt when walking against the wind

8 Gale 62–74 Breaks twigs off trees; generally impedes progress.

9 Severe Gale 75–88 Slight structural damage occurs (chimney-pots and slates removed)

10 Storm 89–102 Seldom inland; trees uprooted; considerable structural damage occurs.

11 Violent Storm 103–117 Very rarely experienced; accompanied by wide-spread structural damage

12 Hurricane 118 and up

Heaviest desolation

Beaufort scale and equivalent wind speed

This weather symbol is a combination of: one symbol for cloudiness and one symbol for wind.

The direction of the symbol for the wind indicates the direction the wind comes from = wind direction (here: NE wind)

Experiment Description/Manual Science Kit “General Science”

Order no. 31500 6

© 2009 Cornelsen Experimenta, Berlin 10.00

Holzhauser Straße 76 Tel.: +49 30 435 902-0 eMail: [email protected] Berlin – Germany Fax: +49 30 435 902-22 Internet: www.corex.de

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