You will need:

• Long string
• Sticky tape
• Balloon
• Drinking straw
• Scissors

What to do:

1. Cut a very long piece of string.
2. Feed the string through the straw. It must move easily.
3. Stretch the string across a room and tie its ends to suitable places, for example a door handle or a chair.
4. Stick two pieces of tape to the straw.
5. Blow up the balloon. Hold the neck and attach the balloon to the straw. The air must not escape.
6. Let go of the balloon. It rushes along the thread at high speed.

Background

The balloon produces a jet of air which drives the balloon forwards. It works the same way as jet engines on airplanes. These engines produce powerful jet of air that drives the airplane forwards.