Exploding bags with baking soda and vinegar-science lesson. They take off like rockets!--kids would love this...um, I would love this
Apples and Handwashing: "We put a clean apple slice in one jar. We passed another apple slice around the class as we came in from recess with dirty hands. We have been observing the two jars in the science center. This is the difference after 8 days - gross! (This picture doesn't really show the mold.)" - A great way to teach about germs.