# Weird Science: Balloon Rocket - Hawaii News Now - KGMB and KHNL

Member Center:

### Weird Science: Balloon Rocket

Things you need:

· Straw

· 10 feet or more of string

· Tape

· Balloons

The experiment:

Please perform this and all experiments under the supervision and with the assistance of an adult!

Tie one end of the string to something solid, like a chair or doorknob. String the other end of the string through the straw then pull it tight and tie it to another support object. Try keeping both end of the string at the same height, so the string is horizontal. Move the straw to one end of the string.

Blow up the balloon, but don't tie it closed, just pinch the neck to keep the air in. Then, using your tape, attach the inflated balloon to your straw, pointing the mouth of the balloon towards the nearest support. Then let the balloon go! What happens to your balloon rocket?

How does it work?

The balloon rocket works on Newton's Third Law of Motion, for every action, there is an equal and opposite reaction, and the law of conservation of momentum. When the balloon contracts, gets small again, it forces the air out of the mouth of the balloon.

Because the air is moving out of the mouth of the balloon, the rocket balloon moves in the opposite direction. There is some friction between the string and the straw, but since the straw is smooth and the weight of the balloon and straw is light, the amount of friction compared to the force of the air coming out of the balloon is minimal.

This is basically how a rocket works. Rockets burn fuel that forces matter out of the end of the rocket, forcing it to move in the opposite direction.