DALLAS-FORT WORTH SECTION OF THE AMERICAN CHEMICAL SOCIETY
CHEMICAL DEMONSTRATIONS First published 1989 Reprinted 1991 New Edition 2012
We hope that you will enjoy using this booklet, whether you are putting together a magic show, doing demonstrations for your students, preparing in-service workshops, or any other chemistry-related activity! If you would like to contact someone here in the DFW section of the American Chemical Society, call the national ACS office 1-800-227-5558 and ask for the name and number of the section chairperson. Please copy this as needed and pass it on. Have fun!
REFERENCES AND EASILY OBTAINABLE BOOKS: Basic reference article: Bailey, P. S. et al., Producing a Chemistry Magic Show, Journal of Chemical Education 52, 524-525 (1975). Available from Amazon: Chemical Demonstrations : A Handbook for Teachers of Chemistry Vol 1-5 University of Wisconsin Press (1982-2011) by Bassam Z. Shakhashiri Hands-On Chemistry Activities with Real-Life Applications: Easy-to-Use Labs and Demonstrations for Grades 8-12, Jossey-Bass (1999) by Norman Herr and James Cunningham Chemical Magic, Dover Books (1993) by Leonard Ford Old but good if you can get them: try Alibris.com Summerlin, L.R. and Ealy, J. L., Chemical Demonstrations: A Sourcebook For Teachers, Volumes 1 and 2 (1985, 1987) Herbert, Don, 400 Experiments in Science Herbert, Don, Mr. Wizard's Supermarket Science, Random House, NY, 1980. Websites: there are many of these, but we like these the best. Chymist.com: go to chemistry in the toy store Chemistry.about.com/od/chemistry magic/chemistry_magic_tricks.htm
CHEMICAL SUPPLY HOUSES These companies do not require minimum orders and are very good about small institutional orders and student orders. Call for a catalog. Sigma-Aldrich Chemical Company Phone: 800-325-3010 St. Louis, MO 63103
THE AMERICAN CHEMICAL SOCIETY IS NOT RESPONSIBLE FOR ANY INJURIES OR ACCIDENTS
DUR-
ING OR RESULTING FROM THE DEMONSTRATION OF ANY OF THE REACTIONS INCLUDED IN THIS HANDOUT. NO DEMONSTRATION SHOULD EVER BE DONE WITHOUT PROPER PRECAUTIONS OR PROPER SUPERVISION.
Minimum Safety Guidelines for Chemical Demonstrations ACS Division of Chemical Education Chemical Demonstrators MUST: 1. Know the properties of the chemicals and the chemical reactions involved in all demonstrations presented. 2. Comply with all local rules and regulations. 3. Wear appropriate eye protection for all chemical demonstrations. 4. Warn the members of the audience to cover their ears whenever a loud noise is anticipated. 5. Plan the demonstration so that harmful quantities of odorous gases (e.g. NO2, SO2, and H2S) do not enter the local air supply. 6. Provide safety shield protection wherever there is the slightest possibility that a container, its fragments, or its contents could be propelled with sufficient force to cause personal injury. 7. Arrange to have a fire extinguisher at hand whenever the slightest possibility for fire exists. 8. DO NOT taste nor encourage spectators to taste any non-food substance. 9. DO NOT use demonstrations in which parts of the human body are placed in danger (such as
plac-
ing dry ice in the mouth or dipping hands into liquid nitrogen). 10. DO NOT use open containers of volatile, toxic substances (e.g. benzene, CCl4, CS2, formaldehyde) without adequate ventilation as provided by fume hoods. 11. Provide written procedure, hazard, and disposal information for each demonstration whenever the audience is encouraged to repeat the demonstration. 12. Arrange for appropriate waste containers for and subsequent disposal of materials harmful to the environment.
Revised 6/4/88. Copyright 1988, ACS Division of Chemical Education, Inc. Permission is hereby granted to reprint or copy these guidelines provided that they are reproduced in their entirety with no changes.
FOR DEMONSTRATORS AND TEACHERS 1. For a 40-45 minute show, choose 10-12 demonstrations. This will fill a class period or a club meeting period. In the lower elementary levels, you may want to cut the show to 30 minutes or so, and concentrate on the more spectacular demonstrations in order to deal with the shorter attention span. A good short set of demonstrations might be acetone and Styrofoam, iced tea or grape juice, and disappearing ink. 2. The demonstrations are listed in approximate order for use in the show. For example, the welcome posters are at the beginning, and the reactions producing fumes and smoke at the end. 3. The available facilities and the amount of material you want to carry around will rule out some demonstrations. For example, if no magnetic stirrer will be available, and you prefer not to bring one, the oscillating clock reaction would not be appropriate. 4. ALWAYS practice any demonstration before using it. If you change reagents, be sure to check the demonstration again. 5. The narrative during the show will depend on your own personality and the circumstances. We do suggest that you include the following: a. the importance of observation in scientific endeavors as part of your introduction. b. With each individual demonstration, ask the class: What did you see? What changed? What do you think might account for the change? c. A brief explanation at the level of the observers on the principle behind the demonstration. 6. Always use good safety technique; wear a lab coat and safety glasses. Emphasize the necessity of caution and healthy respect in any laboratory work. Points requiring extra caution are noted in the handout. A set of American Chemical Society guidelines is included in this handout. 7. If you are interested in putting together your own "traveling show," we recommend choosing a number of demonstrations, compiling a total list of reagents and supplies for them, assembling the supplies and reagents, and devising a method of easily transporting them. A sample list for a good 4045 minute show requiring a minimum of preparation time includes: BALLOONS, DISAPPEARING INK, ICED TEA OR GRAPE JUICE?, POP GUN, BURNING HANDKERCHIEF, A VOICE-ACTIVATED REACTION, COLORED FLAMES, DISAPPEARING ORANGE, BURNING METAL,
LAV-
ENDER FIRE, and VOLCANO. After your initial effort in starting up, you can easily add one demonstration at a time and expand your repertoire.
ESPECIALLY FOR TEACHERS 1. The demonstrations marked (E) are very useful for the elementary grade levels. 2. For your convenience, we have included a table of substitutes, list of references with sources, and chemical supply houses which accept small orders. 3. The section on Kitchen Chemistry by Kathleen Holley is especially adaptable to elementary students. 4. The DISAPPEARING INK demonstration is exceptionally good for teaching the scientific method to any age group. After the "ink" decolorizes, ask the students WHY it lost color (hypothesis). After listing the possible reasons, ask the students HOW you would prove your hypothesis.
GENERAL SUPPLIES
Lab coat
Safety glasses
Gallon of deionized or distilled water (if no water is available at the demonstration table)
Matches or lighter
Bunsen burner or alcohol lamp
WELCOME POSTERS
Small paintbrush
Large sheets of porous paper (blotter or filter paper)
5% KSCN or NH4SCN
5% K4Fe(CN)6
1% FeCl3 in spray bottle (1 g in 100 mL 0.1 M HCI) AND/OR Phenolphthalein solution
O.4% NaOH in spray bottle
1. Spray the paper with water and let it dry before using the indicator solutions in order to prevent wrinkling when message is applied. After painting the messages, papers should also be thoroughly dried. 2. For a RED message, paint with KSCN and spray with FeCl3. 3. For a BLUE message, paint with K4Fe(CN)6 and spray with FeCl3. 4. For a PINK message, paint with phenolphthalein and spray with NaOH. 5. For a DISAPPEARING message, paint one message with phenolphthalein and let dry. Then paint a second message with either KSCN or K4Fe(CN)6. When the sign is sprayed with NaOH, a pink message will appear; spraying with the acidified FeCl3 will then cause the pink message to disappear and the red or blue message to appear.
BALLOONS (E)
Good quality latex balloons
35-50 cm needle
Small "polishing cloth" soaked in glycerin
1. Inflate balloon to maximum size, release a small amount of air to allow molecules some recovery, and tie the end in a knot. 2. Take the needle and wipe it with the polishing cloth as if you are cleaning the needle. At the end of the balloon, where the rubber is thicker and under less stress, slowly push the needle into the balloon using a gentle twisting
motion on the needle. If the needle does not slide easily, more lubri-
cant is needed. 3. Push through to the other side of the balloon until the needle emerges, and withdraw gently. 4. Toss it into the air and pop it with the needle.
DISAPPEARING INK
Thymolphthalein -- few crystals or small amount
10 mL ethanol or isopropyl alcohol
50 mL water
Concentrated NaOH
1. Dissolve the indicator in ethanol and slowly add the water. 2. Add NaOH to bring the pH up and turn the indicator blue. Do not add an excess of NaOH. 3. Squirt on cloth to cause a blue "stain.” The color will disappear in a few minutes as the pH increases as NaOH reacts with CO2 to form sodium carbonate.
ICED TEA OR GRAPE JUICE?
Tannic acid or instant iced tea WITHOUT sugar, sweetener, or lemon
Saturated FeCl3
Concentrated H2SO4
1 large pitcher or beaker, approximately 2 L
6 beakers or glasses, 400 mL each, unobtrusively numbered (size of pitcher and glasses may be reduced proportionally in order to facilitate ease of transporting materials)
A pitcher which holds the contents of three of the glasses
Before the show, prepare the beakers or glasses in the following manner: Beaker 1 — empty Beaker 2 — one drop FeCl3 Beaker 3 — empty Beaker 4 — bottom covered with H2SO4 Beaker 5 — empty Beaker 6 — bottom covered with H2SO4 1. In front of the audience, fill pitcher with water and add enough tea or tannic acid to give the solution a yellowish-brown color. 2. Pour the tannic acid solution--"iced tea"--from the pitcher into beakers 1, 2, and 3. 1 and 3 will remain iced tea, and 2 will turn into "grape juice.” 3. Return the contents of all three beakers (1, 2, and 3) to the pitcher. All of the liquid will turn to grape juice. 4. Pour the grape juice from the pitcher into beakers 4, 5, and 6. 4 and 6, acidified, will turn back into iced tea, while 5, which is empty, will remain grape juice. 5. Recombine all liquid into the pitcher and it will once more become iced tea.
COLORED FLAMES
Burner or alcohol lamp
5% NaCl, KCl, BaC12, SrCl2, and CaCl2 in DISTILLED water in fine-mist spray bottles OR solid samples of the above in finely granulated form.
1. Darken room and spray gently into flame. You may prepare the salt solutions in front of the audience in the spray bottles if you have distilled water available; tap water will usually contain enough ions to cloud the colors. 2. For the solids, place the salt on the end of a spatula and hold it in the flame. This is easier if you are transporting all of your materials with limited space; be sure to use a sufficient amount of the solid.
SUPER SOAP BUBBLES (E)
2 ounces liquid detergent (Dawn works very well)
1/4 teaspoon corn syrup
4 ounces Glycerin (available at drugstore)
4 ounces distilled or deionized water
1. Mix all ingredients together. 2. Bend wire (coat-hanger wire works well) into loops of various sizes. 3. Dip the loops and blow or wave in the air.
NYLON ROPE (good for elementary but takes careful preparation and practice)
A: 0.5 M hexamethylene diamine/2% NaOH in water
B: 0.25 M adipoyl chloride in cyclohexane (may be purchased from Sigma-Aldrich)
Copper wire with small hook on the end
50 mL beaker
1. Carefully layer 25 mL B onto 25 mL A in the beaker. 2. Draw out thread gently from the interfacial layer. May be able to get up to 40 feet with this amount-may want to wind the thread onto the wire as it is pulled out.
DISSOLVING PENNY
Concentrated nitric acid
Penny with date 1982 or older (newer ones are made with zinc)
DO THIS IN A HOOD! 1. Dissolve the penny in concentrated nitric acid. NO2 is generated and adequate ventilation is required. 2. After the penny is dissolved, pour water into the beaker and the deep green solution turns blue.
BURNING HANDKERCHIEF or MONEY (E)
75 mL of a 50/50 ethanol/water solution in a 250 mL beaker
Handkerchief or dollar bill
Tongs
1. Soak the handkerchief or dollar bill in the alcohol solution (may be prepared ahead of time or in front of the audience). 2. Lift out with tongs and ignite; after the flames are gone, the unburned handkerchief remains. WARNING: Don’t talk too long; the cloth or paper will drain and you will really burn money!
DISAPPEARING ORANGE
A: 5 g HgCl2 in 250 mL water
B: 5 g KI in 250 mL water
2 250 mL beakers
OR
A spatula tip full of HgCl2 and of KI, each in 50 mL water using 100 mL beakers
1. Pour some B into A, and then pour from A back into B. 2. Keep pouring back and forth until the color disappears. Note: there should be HgCl2 left undissolved in the beaker so that the solution is saturated; interference with the reaction may be eliminated by pouring the supernatant into a third beaker before mixing. The mercury salts are toxic and should be placed in a closed hazardous waste container after use for ultimate disposal.
THE BOTTOMLESS BEAKER (E)
Acetone
Styrofoam packing material
Styrofoam coffee cup
500 mL beaker
1. Pour 1/2-1 inch acetone in the bottom of the beaker. 2. Place the coffee cup on the surface and watch it dissolve. 3. Stuff handfuls of packing material into the beaker and watch them disappear.
A VOICE ACTIVATED REACTION (E)
Place 250 mL 95% ethanol in a 500 mL flask with 5-6 drops of bromophenol blue. If the solution is not blue, add just enough dilute NaOH to turn it blue. Stopper tightly.
Or
Place 250 mL distilled water with 1-2 drops phenol red in a 500 mL flask. Add several drops of very dilute NaOH to get a red color. Stopper tightly.
1. These flasks may be prepared ahead of time or in front of the audience, using dropper bottles of indicator and of base. 2. Tell the class that the right voice will cause the solution to change color. Pass the flask around the class. Tell the students to remove the stopper, speak directly into the flask and ask it to change to yellow, stopper it, and give it a quick swirl. 3. If the class is large, the swirling may be omitted in order to give more people a chance at it. Notes: Distilled water is necessary for a clear, abrupt color change. Add only enough NaOH to get the color.
BLUE BOTTLE (E)
Prepare solution as follows: 8 g KOH to 300 mL water (approximately I teaspoon to a cup); cool and add 10 g glucose (1 teaspoon). Add a few drops of methylene blue or a matchhead amount of the solid (NOT TOO MUCH). Stopper the flask.
1. Show the class the flask. Shake it vigorously and it will turn blue. Stop shaking it; after a few seconds it again becomes colorless.
POP GUN (E)
Ordinary strength vinegar
Sodium carbonate or bicarbonate (ordinary baking soda will do)
Large heavy-walled test tube or serum bottle with tightly-fitting rubber stopper
Teaspoon
1. Place 10-15 mL vinegar into the container, and dry the rim. 2. Wrap a teaspoonful of baking soda in a single layer of facial tissue to prevent dirtying the rim, and drop it into the bottle. Immediately stopper the tube and point it in a safe direction. (Be sure and practice this one until you find exactly the right combination of ingredients.) 3. If you do not get a loud pop, the cork is probably not fitted tightly enough. Warning: this is very messy--foams all over the place!
WATER OF MANY COLORS (E)
Sodium thiosulfate
Ferric chloride
Distilled water
Prepare two solutions: A. 2.5 grams sodium thiosulfate in 100 mL water B. 1.6 grams ferric chloride in 100 mL water 1. Pour Solution A while stirring into a beaker or jar containing B. The yellow color of B will successively turn deep purple, red, and yellow-green, as the two compounds react to form different-ratio complexes.
BURNING METAL (E)
Magnesium ribbon
Tongs
1. Darken the room and hold the ribbon with the tongs in the flame until it ignites.
LUMINOL (E)
A: 0.25 g luminol in 500 ml 0.1 M NaOH (2 g per 500 mL) (luminol can be purchased from Sigma Chemical)
B: Clorox laundry bleach diluted 1:10 with water
100 mL graduated cylinder or other measuring container
500 mL beaker
Optional: beaker or flask with funnel attachment -- spiraled tygon tubing makes a good show 1. Place 100 mL A and 350 mL water into a 500 mL flask; dim the lights. 2. Add 100 mL bleach solution and observe; OR the two solutions may be poured simultaneously through the funnel.
OSCILLATING CLOCK REACTION
Concentrated sulfuric acid (50 mL)
Malonic acid
KBrO3: (Several spoonfuls of solid)
MnSO4
Magnetic stirrer
1000 mL beaker
Teaspoon
1. Place the beaker on the stirrer; add the sulfuric acid CAREFULLY. 2. Add the following: 3 spoonfuls of malonic acid, 2 spoons of KBrO3, and 1/4 spoon of MnSO4. The solution will fizz and turn brown. 3. Oscillation will begin after a few seconds, and will swing from brown to colorless to brown for several minutes. Notes: there are a number of oscillating reactions; this one was chosen because it is one of the easiest to perform. No pre-prepared solutions are required, and the amounts of chemicals are not critical (thus the use of the spoon), but the mechanical stirring is necessary for any clock reaction to be successful.
THE FOLLOWING SHOULD BE DONE TOWARDS THE END OF THE SHOW SINCE FUMES AND SMOKE ARE PRODUCED.
LAVENDER FIRE, or THE MAGIC WORD (E)
Solid KMnO4 (about a tablespoon)
Glycerin (about l mL)
Evaporating dish or watchglass
1. Put the solid into the container and drop the glycerin onto it. This is a delayed reaction; it will smoke and sputter and finally burst into lavender flames. 2. You can tell the audience that it only ignites when the magic word is given, and ask them to think of and try different words; it will probably take 5-10 guesses before the right one is found! 3. Small amounts are recommended.
Especially for Elementary: Sources and Substitutes for Common Chemicals CHEMICAL
SOURCE OR SUBSTITUTION
Acetic acid
white vinegar
Acetone
nail polish remover (may also be found at hardware stores)
Acid/base indicator
grape juice (or cranberry juice) mixed with water to pink color
Aluminum potassium sulfate
alum (pickling spice at grocery)
Ammonium hydroxide
ammonia (NOT sudsy ammonia)
Boric acid
available in drugstores
Calcium carbonate
chalk
Calcium hydroxide
lime (available in gardening stores)
Copper sulfate
available in drugstores
Dextrose
Karo light corn syrup
Ethyl alcohol
available in drugstores
Ethylene glycol
antifreeze
Filter paper
coffee filters or heavy white paper towels
Glycerine
available in drugstores
Hydrochloric acid
muriatic acid (hardware stores)
Hydrogen peroxide
l2% available in beauty supply stores; 3% in drugstores
Isopropyl alcohol
rubbing alcohol
Magnesium sulfate
Epsom salts
Methyl alcohol
duplicating fluid
Mineral oil
available in drugstores
Naphtha
lighter fluid
Phenolphthalein
can be extracted from Ex-Lax using alcohol
Potassium chloride
salt substitutes
Salicylic acid
aspirin
Sodium bicarbonate
baking soda
Sodium chloride
table salt
Sodium hydroxide
Red Devil Lye
Sulfur
available in drugstores
Tannic acid
can be obtained by boiling oak bark in water, or using instant tea with NO additives (sugar, sweetener, lemon juice, etc.)