Chemistry experiments are a great way to turn elementary students on to science. Kids love to explore by mixing things together, but this can be dangerous in chemistry. Some mixtures are toxic or even explosive! The following experiments are fun, safe, and inexpensive. Kids can mess around with these without harm so long as they follow the safety rules:
RULES: Don’t eat or drink any of the substances in the experiments. Don’t eat food or drink anything while doing the experiments. Keep the chemicals out of your eyes, nose, or mouth. Wash your hands before and after the experiments.
You can grow little crystal gardens in saucers using household chemicals. If you put a disc of black construction paper in the bottom of each dish, some of the inks in the paper will seep out into the crystals and color them.
Any of the following make great crystals: Epsom salts, washing soda, borax, alum, baking soda, salt, cream of tartar.
To make the crystals, you’ll need a small jar with a lid, a saucer for each chemical you use, and some warm water. Half-fill the jar with warm water. Add a spoonful of the chemical, put the lid on the jar, and shake until you’ve dissolved as much of the chemical as possible. Add more if needed. Put a circle of black paper in the saucer if desired. Pour the solution into the saucer and set someplace out of reach of pets and young children. Let the liquid evaporate, leaving the crystals behind. You can set the saucers in a sunny place if you like, but the slower the evaporation, the larger the crystals. Once the liquid has evaporated, use a magnifying glass to study the crystal shapes.
HOMEMADE COPPER CLEANER
Here’s a chemistry experiment that has a practical side. If you have copper-bottom pans, this experiment can be used to clean them!
Put a penny in a saucer and pour a little vinegar over it, just enough to wet the penny. Nothing happens. Now sprinkle the wet penny with a little salt and rub with a paper towel. The penny will turn bright. Why? The oxidized copper on the surface of the penny is insoluble in the plain vinegar. But add salt, and a chemical reaction happens. Salt is sodium chloride. As it dissolves, the “chloride” part combines with free hydrogen in the vinegar to made a weak solution of hydrochloric acid. The copper oxides dissolve in the hydrochloric acid. The solution is so weak that it’s safe to handle, but it’s still a good idea to wash your hands when you are done.
“Black” ink is actually made up of several pigments. It’s easy to separate these pigments with chromatography. You’ll need a black water soluble marker pen, some white construction paper, a clear cup, a pencil, and a pair of scissors.
Cut a strip of paper about 1 inch wide and as long as the cup is high. Cut a point at one end. Just above the cuts, draw a horizontal line using the black marker. Go back and forth several times to make a heavy line that penetrates the paper. Tape the strip to a pencil and set the pencil across the mouth of the cup. Add just enough water that the very tip of the paper strip is in the water. Set the cup where it won’t be disturbed and check every few minutes. As the water creeps up the strip, it will dissolve the pigments in the ink and carry them up the strip, leaving a rainbow of color as it travels.
“MAGIC” JUICE TRICK
This colorful magic trick relies on chemistry. Grape juice contains red pigments that turn green when mixed with a base, such as ammonia, and bright red in the presence of an acid, such as vinegar.
To make the “magic juice,” mix one part purple grape juice with three parts water. This gives a clear, red tint to the “juice.” Prepare five clear plastic cups ahead of time. Cups 1 and 4 are empty. Cup 2 has one teaspoon of household ammonia in the bottom. Cups 3 and 5 have a tablespoon of white vinegar. Remember that ammonia is toxic, so do NOT drink any of the “magic juice” when the trick is over. Pour it down the sink so no one else tries to drink it, either.
When all is prepared, follow this script: “At a party, I served my guests some magic raspberry juice. Andy likes raspberry juice, so I poured him a cup (fill Cup 1 with the juice). But Betty said she’d prefer lime punch. That was no problem, thanks to my magic juice (fill Cup 2, which turns green). When the rest of my guests saw the lime punch, some of them wanted lime punch, too. Since my juice is magic, that wasn’t a problem, either (pour Cup 2 into the pitcher, which turns green). Charlie, though, didn’t want lime punch. He said he’d like raspberry juice. A little magic took care of that (pour juice into Cup 3 – juice turns red). Debbie wanted some lime punch, so I gave her some (pour from pitcher into Cup 4). Ed said he wanted raspberry juice like Charlie had. A little magic solved that (pour from pitcher into Cup 5 – juice turns red). Now everyone wanted another round of raspberry juice. A wave of the magic wand and the wishes were granted.” Pour all the cups into the pitcher. The juice turns red again.
The same pigment in grape juice can be used to do some really cool “magic” painting. To do this, you’ll need white paper, baking soda, warm water, a clean watercolor paintbrush or a cotton swab, another clean paintbrush 1 or 2 inches wide, and some frozen concentrated grape juice.
Let the grape juice thaw. Make a baking soda solution by dissolving 1 tablespoon of baking soda in a pint of warm water. With a clean brush or cotton swab, paint a picture on white paper. Let the picture dry completely. When it is dry, use the wide brush to brush concentrated grape juice on the picture. Amazing! The picture appears in green against the purple background. Enjoy these pictures for a while, but they will be sticky and won’t last more than a day or two.
These activities will get kids started with and keep them happily occupied on a rainy day. Search the internet for “elementary school chemistry” to find more ideas.