Of course, we've long used up the chemistry set's supplies of baking soda and citric acid--fortunately, since we often bake and preserve, we've got both of those materials in our kitchen stores, and I tend to buy vinegar six gallons at a time when it's on sale, since it's about all I use for cleaning. Nevertheless, whether or not you own a chemistry set, I still highly recommend a good stock of nice glass test tubes and cheap plastic eyedroppers; the eyedroppers allow children to have more control over the amount of water or vinegar that they add to their mixtures, and the test tubes are really ideal for observing the chemical reaction.
Experiment #1: Small Scoop of Baking Soda, Eyedropper of Vinegar
It's nice to keep the amounts very small so that the chemical reaction between the sodium bicarbonate and the ascetic acid is easy to observe. Notice the bubbling, notice the fizzing, notice the foam!
Experiment #2: Small Scoop of Baking Soda, Small Scoop of Citric Acid, Eyedropper of Water
I think that this version is even more fun, because the two powders, one an acid and one a base, nevertheless do not react--
--until you add water as a catalyst!
- Look up the chemical formula for each ingredient, then explore the elements that make up the formulas.
- Write an illustrated tutorial for each experiment.
- Use the chemical formulas and the scientific notation of the chemical reaction as copywork or memory work.
- Compare other liquids to water when conducting Experiment #2. Does rubbing alcohol affect the reaction? Does orange juice?
- Play with the reaction as a sensory experience, as long as you don't have any cuts on your hands. Neither vinegar nor citric acid are strong enough to hurt healthy skin, so get out a big baking pan (or go outside--I wish!) and make big piles of baking soda, on which you drop vinegar rain.
- Add powdered tempera to either the baking soda or vinegar to make fizzy paint.
- Make and erupt the traditional baking soda and vinegar volcano.
- When the kiddos were finally finished with their play (nearly an hour later!), they asked me what they could do with all their test tubes and mason jars of vinegar. I suggested that they use it to scrub the kitchen floor--and they did!