Question

Are the fluid properties associated with the balloon the same as those that affect a rocket? Why or why not?

Answer 1

Though complex chemical formulas aside, rocket fuel is based on a simple idea: create enough power to push an object forward. This movement works in part because the power created by burning fuel is focused in a single direction. By controlling the direction that force goes, you can create thrust. When a space shuttle launched, the power is focused down, forcing the shuttle to move in the opposite direction.

When you blow up a balloon, you force extra air into it, creating higher air pressure inside the balloon than outside of it. Given the chance, the air molecules will move to a lower-pressure environment—which is why, if you let go of a balloon's opening without tying it off, the air you added will rush out again. The air from inside goes in all directions, distributing the force so that none of it is that strong in any one direction.

But if you allow the air to exit through only one small hole, the force will be strong enough to propel the lightweight balloon in the opposite direction.