Balloon Rocket
		Materials: A balloon Some string A straw Some tape

Procedure: Thread the string through the straw and stretch it across a large horizontal distance. Inflate the balloon but do not tie it. Tape the inflated balloon to the straw. Take the straw back to one end of the string and release the balloon.

Explanation: The balloon can be taken as a control volume. Air escaping the control volume at high velocity will produce a net motion in the opposite direction.