Sometimes the changed food is safe to eat. In the first experiment, you will investigate microbes that can change food. These tiny life forms are too small to see with the human eye. They are all around us, and most do not harm us. But large numbers of some microbes growing in food can make us very ill.
Yeast is a tiny life form that grows quickly under the right conditions.
Add 1 teaspoon yeast to each glass. Stir each well. Let set undisturbed for at least 5 minutes. Record your observations in the Scientist in Action page at this time and again 10 or 20 minutes later. Ripening Plant foods ripen and change as they grow.