Exploratorium
Exploratorium: Science Snacks: Spinning Blackboard
Explore the effects of drawing in a straight line within a rotating frame of reference. This activity requires a turntable. If this is unavailable, a cake turntable with a glued-on center post might work as well.
Museum of Science
Museum of Science and Industry, Chicago: Activities: Make and Fly a Helicopter
Print and cut out the template for the helicopter. Then experiment with adding and subtracting weight, or changing the shape of the copter or the blades to see what makes it fly best.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Momentum Conserved
This site by the Illinois Institute of Technology gives a Lab activity in which young scholars use a variety of toys to discover Newton's second law and momentum conservation. Newton's cradle, skate boards, and a toy motorcycle are...