You probably know that washing your hands helps stop you from getting sick.

But why is that? First, lather from soap traps the germs, DIRT, and oil on your hands. Then, hot water and scrubbing your hands together rinses them away. In this activity, you will be able to see how washing your hands stops germs from growing on slices of bread.

First, write on one bag “control” with a Sharpie. Write on the next bag “clean hands,” and write on the last bag “dirty hands.”

Use kitchen tongs to put a slice of bread inside the “control” bag. Make sure not to touch the slice with your hands!

Next, rub your dirty hands on the next slice and put it in the “dirty hands” bag.

Put your slices in a safe place. After five to seven days, bring them out and observe! Which slice has the most mold compared with the “control” slice? Is there more mold on the “dirty hands” or the “clean hands” slice?