Balloon powered boat

What you need

To do this activity you will need to gather:

• a margarine container
• a balloon
• a straw
• a rubber band
• plasticine
• scissors
• something that will pierce the margarine container to make a hole big enough to fit a straw through.

What to do

1. Find a clean, rectangular, margarine container and carefully make a hole in the centre of one of the shorter sides about 1 cm from the bottom.
2. Cut a straw in half and insert one end into the neck of a balloon. Fix the balloon firmly to the straw with a rubber band.
3. Push the straw through the hole in the marg container and seal it in place with plasticine. Weigh the back of the marg container with more plasticine in the centre. Blow the balloon up through the straw and pinch the end to keep the air inside.
4. Put the boat in the water, let go - and away she goes.

This is an example of Newton's third law of motion - every action has an opposite and equal reaction. The air rushing out of the straw is the action, and the equal reaction is the push against the boat in the opposite direction.

Can you improve the design of your boat?

Source: http://www.csiro.au/en/Portals/Education/Programs/Do-it-yourself-science/Physical-sciences-activities/balloon-boat-activity.aspx