5 - Rocket Balloon

The Rocket Balloon brilliantly demonstrates Sir Isaac Newton's Third Law of Motion...and it's great fun too!

What you will need

  • 1 balloon
  • 3m string
  • 1 drinking straw
  • Short length of sticky tape

How to do it

  • Thread the string through the straw.
  • Tie the string between two fixed or heavy objects (door knob, chair, table leg etc) so the string stays taut during the experiment.
  • Inflate the balloon but DO NOT tie off the neck. Round balloons work but try a long balloon for the best results.
  • Pinch the balloon to stop the air going out and use the sticky tape to secure the cut piece of straw to the balloon pointing towards the neck.
  • Take the balloon to one end of the string and release it…the balloon should travel along the string like a rocket!

What is happening?

This experiment demonstrates Sir Isaac Newton’s Laws of Motion. In Newton’s Third Law, he wrote every action creates an equal but opposite reaction. When the balloon is released, the air pushes out of the back of it. This force is called ‘thrust’.

Share your experiment...

Why not share your results on our Facebook page or email This email address is being protected from spambots. You need JavaScript enabled to view it.. Our Boffins would love to see your scientific results!

Remember!

All experiments must be conducted in the safest possible way. An adult must be present wherever it states one is required. Never do anything dangerous with chemicals or fire for your sake and those around you.