Richard H. Hanson University of Arkansas at Little Rock Linle Rock, 72204
The idea of putting some rather unusual and spectacular chemical reactions together into aperformance and calling it "Chemical Magic" has been around a long time. Generally these programs are geared for entertainment a t the high school and college levels. This paper is a report of a program I developed for elementary school teachers and students. The experiments are mostly classical "magic" demonstrations, but they are used as instructional aids rather than as entertainment and are directed a t a younger audience than previously reported. This program developed as a result of having the opportunity to spend 90 min with 40 elementary school teachers enrolled in a science education workshop this past summer. These were people with little or no ~ h e m i c a i t r a i n i nwho ~ would he introducing chemistw to their pupils in the lower elementary grades. The best service I cou-ldperform for this group, I reasoned, would be to show them chemistry can be made fun for both teachers and students by effectively demonstrating and explaining chemical principles rather than contributing to the myth that chemistry is mysterious and magic, and by alerting them of laboratory safety problems as well as teacher responsibility in the lab. Demonstration ma' ~the ~ unusual terials were taken from the classic s o ~ r c e s of and dramatic ~ . "chemical ~ ~~-~~ - as well as from recent a r t i ~ l e son magic." Safety topics came from the "Safety in the Chemical Laboratory" series published in this Journal. The program presented below was given to the teachers. It was enthusiastically accepted, and as a result I have been invited into many of their classrooms to perform for their students. A short form, consisting of only those experiments marked with an asterisk, can quite easily be taken into the class and completed in 40 min. T h e concepts developed are listed with the experiments given in parentheses. Participation by members of the audience is encouraged whenever the demonstration is appropriate. ~
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1) Chemical Reaction-Chemistry is the science of changing one
compound into another. This process is called a chemical reaction. One way to tell a reaction has occurred is toobserve acolor change or the formation of a precipitate (Patriotic colors,* Orangeade'). Reactions can occur between gases (white smoke'), solutions (the first two), solids (magic powder*) or between solids and solutions (blood red*).
Chemistry is Fun, Not Magic
2) General Properties of Chemieals-Eachsubstanee has a list of physical properties associated with it. Four such properties are salubility (Styrofoam cup', Ammonia fountain?, heat of solution (Endo-exo)..vanor (Boil cold water) and refractive index . oressure . (Disappearingglass). 3) Chemical Equilibrium-Reversible systems can be changed by the addition of heat (hot and cold color*)or by the addition of extra amounts of a reactant (hlue bottle*). Some systems are irreversible (volcano*). 4) Rate of ReactionsTime required for a chemical transfornation can be controlled by varying the concentrations (clock reaction*). Other reactions are nearly instantaneous (nitrogen triiodide). 5) Classes of Compounds-Chemicals can be grouped into classes that have similar properties because of similar chemical structures. Acids and bases are two examples. Indicatan can distinguish between these types of compounds (grape-juiceindicator'). 6 ) Specific Compounds-Some compounds are sa important that they are singled out for extensive study. Water is one such substance. It has very unique characteristics (Kleenex). 7) Types of Reactions-Chemicals are changed into other compounds by one of many general types of reactions. Oxidation is the name given to one type. These reactions can he slow and dull (acid writing, black foam') or they can be exciting (blue flare,' sugarchlorate).
Directions for the experiments are given in order of appearance. Patriotic Colors. Pour a dilute aqueous ammoniasolution into a phenolphthalein solution (0.1 g phenolphthalein in 100 ml of ethyl alcohol and diluted with water) to get red; into a lead nitrate solution (2 gI100 ml of water) to get white; into a copper sulfate solution (2 gI100 ml water) to get hlue. Orangeade. Pour a potassium iodide solution (15 g into 200 ml water) slowly while stirring into a mercuric chloride solution (5 gl300 ml of water).
Ford, L. A,, "ChemicalMagic," T. S. Denisan and Co., Inc. Minneapolis, 1969. Alyea, H. N., and Dutton, F. B., "Tested Demonstrations in Chemistry," 6th Ed., Division of Chemical Education, Easton, 1965. Berka, L. H., J. CHEM. EDUC., 51,262 (1974). Bailey, P. S., Bailey, C. A., Anderson, J., Koski, P. G., and Rechsteiner, C., J. CHEM. EDUC., 52,525 (1975).
Volume 53, Number 9.September 1976
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White Smoke. Hold concentrated solutions of ammonia and hydrochloric acid close to each other. Magic Powder. Add 2 g of lead nitrate powder to 2 g of powdered potassium iodide in a test tube, stopper and shake. H h d Red. Coat a piece of paper with a potassium thioctranatesolution (5ail00 ml water). Allow time for it to drv. Dip your finger i n t i a solution of ferric chloride (5 gI100 ml water) and write on the oaoer. S1)rofoom Cup. pour water into one cup and an organic solvent rhrnrene, rarlxjn tetrachloride, etr.) into another. He sure to use a receptacle to ratch the organic solvent. Ammonm Fountain Refer m reference (2). Endo-Exo. Put 1 g ammonium chloride in a large test tube. Add 10 ml water. Stopper and shake. Do the same with 1g sodium hvdroxide in another tube. This reouires student ~~-~ participation. Boil Cold Water. Add 100 ml water t o a 500-ml flask and boil lor 2 min. Remove from the henter and stopper. Put the flask in a mixture of icu and water. Be sure the flask is t a ~ e d in case it hrenks while under pressure. l)i.wDoeorinr (;loss. h r e x alass. when d i n ~ e dinto a solution b i 51% carbon tetrachloride and 49% benzene, will "disappear". Hot and Cold Color. Dissolve 3 g cobalt chloride in 500 ml of ethyl alcohol. Add water until the solution is pink. Heating on a hot plate will now cause the color to change. (CAUTION: DO NOT HEAT OVER AN OPEN FLAME BECAUSE O F T H E F I R E HAZARD!) Blue Bottle. ~ i s z v 9e potassium. hydroxide in 250 ml water. Add 9 g dextrose and a few milliliters of 0.1% aqueous methylene blue solution about 1hr prior to the performance. Gentle shakine causes a blue color t o amear. Volcano. ~Ylesome ammonium dicgomate on an asbestos ad. Put a wick (maenesium ribbon or Daoer soaked in alcohol) in the center ofthe pile and light. ?urn off the lights.
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578 / Journal of Chemical Education
Clock Reaction. Dissolve 2 g starch in 100 ml of water, boil, and filter. Add one solution (0.5 g potassium iodate in 300 ml of water) to another (0.6 g sodium sulfite, 6 ml dilute sulfuric acid, 15 ml starch solution, and 300 ml water). Use a watch to time the reaction. Grape-Juice Indicator. Add 5 ml of commercial grape juice to 50 ml of vinegar and ammonia. Kleenex. Spray commercial water repellent (3M's Scotchgard or Amway's Dri-Fab) on a Kleenex and let dry. Hold the Kleenex horizontally in the air such that a cradle is formed and have another person pour water into the cradle. Then add one drop of a commercial liquid surfactant (Amway's L.O.C.) to the water on the Kleenex. Acid Writing. Use a glass stirring rod as a pen and concentrated sulfuric acid as the ink. Write on paper. The message will appear in a few minutes. Black Foam. Add powdered sugar to a 200-ml heaker until half full. Pour 15 ml of concentrated sulfuric acid on the sugar. Blue Flare. Mix 1e of drv ammonium chloride with 4 e of dry wnmonium nltrate. Puur inm a mound on an asbestos pad. Cover the mound with zinc dust. Put a dror, of waler on the pile and stand hack. B E VERY CAREFUL WITH THIS EXPERIMENT! Sugar-Chlorate. Mix half a gram of potassium chlorate with an eaual amount of eranulated suear. Put the mixture in a mound on an aihevtoi pad. I'ut n drop of conrentrated sulfuric acid on the pile and stand hack. T o produce a red flme,add a littlesrrmtium nitrule m the mixture. RE VERY CAREFUL WIT11 THIS EXPERIMENT! The Safety handout can he received by writing the author with a request. Acknowledgment
Dr. Rohert Eliason of Southwest Minnesota State University provided the idea for this program.
