An amazingly simple but extremely effective way to demonstrate NewtonA's Third Law. Blow up the balloon and attach the hub to the blade assembly and this jet reaction copter is all set to soar! With fresh balloons, it will fly about 2 stories high. Newton's Third Law has to be applied twice in order to explain the upward motion of the helicopter. The exhausted gases force the fan to rotate, driving the air downward. The reaction of wind, in turn, provides the lifting force for the helicopter.
