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Adult-Assisted Chemistry Experiments These experiments require adult supervision and/or assistance as they deal with cooking and/or chemicals that require special handling. Magical Disappearing and Reappearing Invisible Ink This is from the Book Chemically Active! by Vicki Cobb You will need: To make the starch solution, mix 1 teaspoon of cornstarch into 1 cup of water. Heat and stir until the cornstarch is completely dissolved. Add another cup of water. This can be stored in the refrigerator for a couple of days. Be sure to give it a good shake before measuring out your tablespoon for the experiment. Put the starch solution, peroxide, water and vinegar into one glass. It will look like water. Put a few drops of iodine in the bottom of one of the other glasses, and 1 or 2 drops of hypo solution in the bottom of the third glass. Pour the invisible ink into the first glass. The iodine will react with the starch to give the blue-black colour that is a test for starch. Now pour it from there into the third glass. The hypo will form a colourless compound with the iodine which frees the starch (which is also colourless) so the liquid goes clear again. While this is happening, the hydrogen peroxide is also breaking down and adding oxygen to the mixture. The oxygen makes a more permanent compound with the hypo than the iodine, so the hypo leaves the iodine which becomes free again to react with the starch. So after about 15 seconds, the liquid turns blue-black again. If you dip the end of your wand into the hypo solution and use it to stir the liquid, it will go clear again until the oxygen combines with the extra hypo. Hypo is the photofinishing chemical sodium thiosulphate. I was able to talk the owner of a photography store into selling me a small baggie; otherwise you need to order it from a chemical distributor in huge quantities. It can be disposed of down the sink or toilet, and as long as you don't ingest it, it is safe for use. If you are unsure, please ask for a WHMIS safety data sheet when you buy the hypo. Dry ice, which is really frozen carbon dioxide (the stuff we exhale, and also a major greenhouse gas), sublimates at room temperature. That means that when it hits the heat of the room, it changes directly from a solid into a gas. This gas is heavier than air, so if you are working with dry ice, don't leave any small children or pets at floor level as they may not get enough air. Be sure to keep your room ventilated. It is not toxic to breathe, but it isn't air either! When dry ice sublimates, it makes a foggy trail across the floor. This is often used to create fog and smoke effects in the theatre and also at Halloween. When it warms and sublimates, it also expands. The following experiments take advantage of these properties to make some pretty cool effects. For this you will need: Soak your sponge in the water and squeeze it out, then dribble dish detergent on it so it becomes not quite saturated. More Fun with Dry Ice (aka frozen Dementor's breath) Try and make a spoon scream by first running it under hot water, then pressing it against a dry ice pellet. You can also use a clear film cannister (be sure it is the clear kind that the top can easily pop off) to make a tiny rocket fueled by dry ice. Pop a pellet of dry ice inside and push the lid on. Then stand back and watch it go. Be sure to do this outdoors, and aim it away from all living things. We made dry ice ice cream. The main trick to this is to use a very large bowl, as it will increase dramatically in volume (~4 times the volume at the very least). It also gets very misty. We used the ice cream recipe on the edible concoctions page, and added dry ice right into it. This requires continuous stirring until the mixture thickens. It is best to pop it into the freezer for a while before eating to be sure that all the dry ice has sublimated before eating. You can monitor this by putting a few pellets into a container beside the ice cream in the freezer. When they disappear, the ice cream is ready. You can also make rockets with dry ice. Be sure to only use containers that do not seal (no plastic or other bottles with lids). A film cannister with a pop-off lid works well. The dry ice rocket will work like the baking soda rocket, the only difference being the fuel you use. Since the container is quite small, you will need to use a small chunk of dry ice. To break dry ice, have an adult use heavy leather or other natural fibre gloves and insert larger pieces into a pillowcase. Tie shut. Wearing safety glasses, use a hammer and strike the dry ice in the pillowcase. Remove the smaller pieces with gloved hands. Red Cabbage Water Indicator Rainbow Potion Ingredients: Prepare the cabbage water by chopping up the red cabbage into tiny chunks. Boil it until the colour of the leaves has faded quite a bit, then strain out the cabbage. Use it for a soup or casserole. Keep the red water; this will be our main ingredient. It can be cooled and refrigerated overnight, or frozen if you won't be using it immediately. Pour a few spoonfuls of the cabbage water into your container. Add a small spoonful of powdered laundry detergent and stir. Note the change. Add a couple of squirts of vinegar, stir and observe. Add a small spoonful of baking soda and stir. Observe. Add a pinch or two of pop rocks. You may also wish to add yellow raisins and/or gummy worms, although they do not cause much change to the potion. To use this experiment for a wizard or Halloween party, use names such as: Powdered Root of Asphodel, Ground Bicorn Horn, Pulverized Dragon Eggshells, Leech Juice, Boomslang, Basilisk Venom, Shrivel Figs, Night Crawlers, Yeti Dandruff, etc. for the various ingredients (let your imagination run wild!). Materials: |
