Air in Motion-- help?

blow up a balloon and use your fingers to keep the air in. while holding the balloon and the other end of the string or line, back away from the tied end until the line is straight. have your helper tape the balloon to the straw with the finger-held end on the balloon next to your hand holding the line. let go of the balloon. explain what happens to the balloon and the air in the balloon. explain why the balloon moved and why it stopped. relate this to the space shuttle and how somehow it relates to pressure gradients in the generation of winds.