Yeast may look like sand, but add some lukewarm water, and it’s something else entirely. It’s alive!
Get your child excited about science and teach them about a fascinating and extremely beneficial little organism that does so much for us. Your kid's favourite peanut butter and jelly sandwich wouldn't be the same without yeast. This experiment for kids is especially good for kindergarteners, who are fascinated with that timeless question: "Is it alive?"
3 teaspoons of dry yeast
3 clear, reusable ziplock bags
¼ cup of lukewarm water
2 teaspoons sugar
Prepare your experiment surface – something clean and dark, maybe a sheet of plain paper, in a well-lit spot. Pour a teaspoon of yeast onto your surface and, together with your child, take a good look with the magnifying glass. What can you see? Study how the yeast doesn’t move or seem to breathe – indeed, it doesn’t seem alive, does it? When you’re done, carefully sweep the yeast into a ziplock bag and put aside.
Pour out another teaspoon, and mix it with one teaspoon of dry sugar. One way we can tell if things are alive is if they move together, or even absorb one another. Grab the magnifying glass and take a look again. See anything alive? (Probably not!) Once you're done taking a look, pour the dry sugar and yeast into the second ziplock bag.
Pour the third teaspoon of yeast straight into your last ziplock bag. Add a teaspoon of sugar, and then (making sure your bag has no holes) pour in the lukewarm water. Zip the bag securely shut.
Put all three ziplock bags in a sunny window for approx 20 minutes, and then check them out: the first two bags will show no change in the yeast, but that third bag will be… well, transformed. The bag should be puffy, and the yeast will have mostly dissolved. Try pouring a little of the solution into a clear bowl sitting on your dark surface, and have a look with the magnifying glass.
Yeast really is, in fact, alive. It’s a one-celled member of the fungus family, and when you add water to it and give it a little sugar for food, the organism "burps" and releases carbon dioxide—the gas that makes the bag puff out and makes sodas fizzy and bread fluffy.
If you want to make the most of this experiment, try baking one of our breads. If there was ever any doubt before, this will remind your kid that science can be totally delicious!