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Did you know that there are living things so small that we cannot see them without looking through a microscope? These little living things are called microbes. Microbes can do many incredible things for us and around us. If you’ve ever helped your mom or dad bake bread, you knowthey use yeast to help make the bread rise. Yeast is a small one-celledplant, or microbe, that will help us with this project.

All you’ll need for this experiment are two jars (medium size) withlids, a pack of yeast and a banana. Just make sure you don’t take thebanana that your mom packed in your lunch!

Here’s what you do:

Take the banana and slice it in half lengthwise so that you have twopieces about the same size. Make sure it’s ok with your mom to use aknife. (You might have to ask her to help.) Peeloff the skin and throw it away. Place one banana slice into each jar.Sprinkle some of the yeast onto one of the slices. Loosely replace thelids. You don’t want to close the lids too tight. Place the jars in awarm place like your kitchen window sill or maybe some place in yourroom. If you’re not sure where to put it, you can ask your mom forhelp. Leave the jars alone and check on them in a few days. You willsee that the banana that you sprinkled with the yeast is shrinking anddecaying quicker than the slice with no yeast.

Here’s what happened:

The yeast that you sprinkled, eats the banana and breaks it down intodifferent kinds of raw materials. Carbon dioxide gas is one of theseraw materials that is produced by the yeast. Yeast is called adecomposer because it can breakdown food, wastes and dead organisms intoraw materials. Yeast is one of many small decomposers that help us tobreakdown and recycle raw materials. Did you notice that the slicethat wasn’t sprinkled is staring to decay too? There are some yeastspores and other microbes that are always in the air that landed on theslice because the jars weren’t tightly closed.

Pretty cool! But don’t worry you won’t start decomposing in your sleep!