Pendulum Painting - Martha Stewart Kids' Crafts Good way to teach air resistance and and Newton's Laws. have students summarize the effect of forces on their product and then they have a piece of art work to take home!
You can blow up balloons with Pop Rocks because they contain a small amount of pressurized carbon dioxide gas.
This is why I keep all my magazines! I remember using magazines multiple times for school projects! But this-Really cool idea - cardboard doll house with magazine pictures. Could do with a firehouse/something more boyish, too.