Day 5. Make! A rocket balloon

February 20, 2015

Rockets use the basic scientific law of action-reaction. As burning gases from the rocket engine blast outwards, they push the rocket forwards. Burning needs oxygen, but space has no air and therefore no oxygen. Rockets take liquid oxygen or an oxygen-rich chemical called an oxidizer.

Want to know how to make a balloon rocket? It’s super easy and great fun!

You will need
String, drinking straw, long balloon, sticky tape

How to make
1. Tie one end of the string to something solid and secure, like a doorknob.
2. Thread the string through the drinking straw and tie the other end to something solid and secure several metres away, so that the string is tight.
3. Blow up the balloon and, while holding the neck, stick the balloon to the drinking straw with the sticky tape.

How to use
Let go of the balloon and watch it fly along the string. The air escaping from the balloon pushes it along, like the fiery jet of burning gas from a rocket. The pushing force that moves the balloon and a real rocket is called thrust.

Discover how a rocket launches in more detail here.

Did your rocket blast off? How far did it go? Let us know about your science activities for kids in the comments section below or on Facebook or Twitter.