A challenge in high-school chemistry.

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  • A CHALLENGE IN HIGH-SCHOOL CHEMISTRY

    E. R. HARRINGTON . . The Albuquerque High School, Albuquerque,

    New Mexico

    SOME 15 years ago the writer had .two chemistry students who wanted to do extra work in chemistry on Saturday. He was working in the laboratory himself so he told them to come. When they arrived he found that their plans were somewhat hazy so he took their presence as an opportunity to promote the methodical investigation of the chemical processes. As a student the writer had been a disciple of Lome, Scott, and Brinton-all excellent analytical chemists-and he took the two volunteers as candidates for scientific in- doctrination.

    The idea seemed to work. The two students grew to ten or more, and the program went on year after year. Now the instructor appears a t the laboratory every Saturday and about half of the Sundays. The students are all volunteers. They have access to the instructor's books and to the equipment that the Department Kas or can borrow. The instructor outlines suggested things to do and oversees the work, but healso sets the stu- dents upon various research topics which lead them many places in search of information. The students be- come familiar with the libraries in the instructor's office, the High School, the Soil Conservation Service, and the State University. The writer believes that re- search need not be delayed until the student is ad- vanced in college work, and the results obtained seem to bear out this conclusion.

    Many high-school students take chemistry only for credit, just as many do also in college. Such children must be taken care of to the best of our ability; but the' able, the interested, and the willing should be given an opportunity to work to the limit of their capacity. Thomas Edison accused the American school system of "polishmg the brick-bats and dullmg the diamonds" and he may have had some justification. We try, how- ever, to put a polish on those diamonds, and this extra- curricular chemistry offers us such an opportunity. In addition to our Saturday and Sunday chemistry meet- ings we have now established one of our school's chemis- try sections for our "top" students.

    This "top" chemistry class is entered after an inter- view which includes a look a t the student'sfuture plans, his past accomplishments, and his interests. After ad- mission the course begins without further formalities. No attempt is made to "sugar coat" the pill of knowl- edge. Thirty or more students are there to learn chemistry, which is admitted to be a difficult subject. The formal standard approach is made with much added emphasis on'mathematical principles and ac- curacy of observation and measurement. Balancing of equations, weight problems, gas problems, atomic and

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    molecular structure, the laws gover?ling reactions, are to be looked on as powerful tools to gain what we want- a knowledge of chemistry.

    When molecular weights are taken up they are de- termined by the lowering of freezing point, by Dumas bulb, and by the Victor Meyer method. Experimental care is stressed, speed being no object. Weighing on the analytical balances is started within three weeks. The instructor teaches several students how to weigh ac- curately to the fourth place. They in turn teach several others under the instructor's supervision. The second group then teaches a third group under the supervision of the first group, and so on. From time to time the instructor checks back on every individual to see that he has learned properly.

    When acids and bases are taken up their relative strengths are determined by conductivity. Later their concentrations are determined by titration against primary standards prepared by the student. The students prepare their solutions, determine their normalities, and these are checked by the instructor who uses the common standards. The students become familiar with indicators, pipets, burets, weighing bottles, desiccators, and volumetric flasks. They de- termine strengths of commerpial'vinegar, battery acid, commercial lyh, and other acids and bases a t hand.

    The intricacies of the oxidation-reduction process are taken up, with laboratory work on reduction of copper oxide, checked by careful weighing. The percentages of iron in hematites and magnetites are determined by titration against potassium permrmganate and the re- sults are checked against gravimetric determinations. Sulfur dioxide is oxidized by the contact process using a platinum catalyst. Sulfuric acid is also manufactured by the lead chamber process and the concentration of the manufactured acid determined by titration against a standard base.

    Electrochemistry starts with conductivity of solu- tions and the electrolysis of water but goes on through the determination of the electrochemical equivalent, and branches out into dt?termination of copper in brass and bronze. In our laboratory we have produced lithium, sodium, and potassium. Calcium carbide and carborundum have been made and phosphorus has been extracted from bones. A homemade Cottrell precipita- tor has been made and used.

    Analytical work comes in for considerable attention. We go through the common qualitative processes not just as "cook-book" procedures hut with the back- ground of hydrogen-ion concentration and the theory of sulfide precipitation. We hope that pH and ioniza-

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  • 296 JOURNAL OF CHEMICAL EDUCATION

    tion constants and ion suppression will mean something to these students. In gravimetric work we have stu- dents who turn in first-rate determinations of alu- minum, iron, silicon, and calcium, together with some alkaline fusions of silicate minerals. For such fusions our single platinum crucible gets a terrific workout. If we seem to concentrate unduly on accurate weighing and measuring it is because.we wish to check those weight problems so that they become real and vital and not just di5cult tasks to be done.

    In organic work some determinations are made of heat of combustion of some safe compounds. Com- mercial coal analyses are made and some rough at- tempts a t organic analysis are carried on with our own interpretation of a combustion apparatus. We carry on some work in the oxidation and reduction of some or- ganic compounds to secure familiarity with the intricate processes studied in college.

    The course does not omit the romance of chemistry or the spectacular nature of its applications. We en- deavor to present the struggles of the past, the suc- cesses of the present, and the great work which must be

    carried on in the future. At the same time we do feel that cKemi6try is a study which demands much of the student. There are certain basic principles which must be learned, whatever the drudgery may be. No amount of "romauce and beauty" will ever%ake the place of this, and for that reason those who choose to take this special course do a lot of work which students in other courses do not do.

    The writer has had 15 years to follow these students as they have gone on to colleges or into various trades. He has made numerous checks in the past with the head of the chemistry department of the State University. He has made less frequent checks with other institu- tions which are not so accessible. The results are the s a m e t h e good students do well in college work. The loafers in high-school chemistry do not last long in college chemistry. The students who began their re- search in the high-school laboratory on Saturdays and Sundays went on to become chemical engineers, elec- trical engineers, aviators, soil specialists, workers in atomic physics, doctors in chemistry, physics, and medicine.