edited by P n m i c i n J.
cherni~tryfor kid/
SMITH
United States Air Academy High Schwi United States Air Academy. CO 80840
What Chemists Do Gary G. Glachlno Connecticut College. New London, CT 06320
Solutions Used in the Experiment Unknownsa
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There is little ouestion that recent vears have seen a de- - - - - - -clining interest in science, and that much of society has develoned a neeative attitude toward chemistrv and chemicals. (I),~ d h Overend n has In a'recent k t e r to THIS JOURNAL indicated that the neeative asnects of chemistrv are often stressed in elementary"achools,k d he suggests that chemists should do something to counter this. His letter has prompted me to describe a very successful activity that I have performed several times with elementary school children. The activity is called "What Chemists Do" and, although it was designed for children in a aifted or enrichment program, it should he suitable for any students in grades 46. Thecontent is flexible and may he adjusted to suit any environment or range of abilities. Because it is open ended, the time requirements are also very flexible, but 2-2s hours seems to he optimum. The session begins with a brief lecture and several demonstrations. Although the exact demonstrations may depend on the facilities andtime availahle, some examples are provided to illustrnte the flavor of the lecture. Numerous other demonstrations may be found easily in several sources such as the hooks by Alyea and Dutton ( 2 ) and Chen (3).Safety considerations and the success of the lecture demand that the demonstrations all he well rehearsed and that the physical facilities and seating arrangement be known in advance. During the lecture, the activities of chemists are arbitrarily divided into four groups, which are described in the order below. ~~~~
~
0.01 0.01 0.01 0.01 0.10
M AgN03 MCU(NO~)~ MFe(NO& MNi(NO& MPb(NO&
Test Soiutims (A) 1 MNHJ (8) 1 M NaCl (C) 0.1 M Oimethyigiyoxime (eIhami) (D)0.05 M KSCN (E) 0.1 MK2Cr0,
AU ~ ~ m n m t i o n am s approximste. mosa of me metal tom refer toms final mccmbatkm In me unkmrwm.
addition of sulfuric acid to a mixture of sugar and potassium chlorate. Very small quantities are all that are required to make the point. Perform Sclenilflc Research (The Methods ot Sclence) The methylene hlue-glucose "Blue Bottle" experiment ( 4 ) not only fascinates the students, but also it is an excellent vehicle to illustrate how hypotheses can he proposed and tested (5). Hypotheses which the students suggest invariably include: "There's something on the cork" (cover it with foil), "The stirring causes it" (use a stirring rod), "Mixing with gas" (try bubbling in nitrogen or carbon dioxide or natural gas before air and/or oxygen). Necessary gases can he stored in a balloon attached to a piece of rubber tubing equipped with a pinch clamp and a Pasteur pipet. The time available and the This feature is desionedto encavaae our readers to become involved
Work Safely
Emphasized are the need to wear eye protection, the prohibition of food and drink in the laboratory, and the need to thoroughly wash up after working with chemicals. The fact that chemicals should not he randomly mixed together is illustrated by causing a few (unexpected) violent reactions to occur. Two reactions which have been effective are the mixing together of red phosphorus and potassium chlorate and the
Share your pagram with the rest of the readers. We further challenge mOSe who have not n*lde me first step to use mese p q a m s to deveiq, a system which will work for you and the kids in your communily. R e SPO~SBSof the children to lhe activities would be of particular interest. In this way, this feature can provide mechanisms fw innoducing more chemistry to children and thus society.
Volume 60 Number 9 September 1983
743
background of the students will determine the extent to which the cause of the blue color will be identified. After discussing how scientists in general do research, it is pointed out that chemists are particularly interested in the behavior of atoms and molecules. This leads to a very brief discussion of the size of molecules and the states of matter. The latter, a potentially uninteresting topic, becomes quite interesting when they see some of the properties of liquid air (nitrogen). The usual demonstrations include pouring some into a beaker and unto the floor as well as freezing a flower and some rubber. A colorful or magic demonstration can also he included in this section to show how learning about molecules can he fun. One which has worked very well is to add a dilute solution of HCI containing phenolphthalein to an apparently empty heaker. Because
