Ages 6+ · 15 minutes · Difficulty 1 of 3 · Grown-up help: A grown-up tapes the straw.
Balloon rocket
See thrust with a balloon on a string.
Safety. Do not let anyone put the balloon in their mouth and inhale. Keep the string away from necks.
You need
- A balloon
- A long piece of string
- A drinking straw
- Tape
Predict
Will a bigger balloon go farther than a smaller one?
Do this
- Thread the string through the straw. Tie the string tight across a room.
- Blow up the balloon. Do not tie it. Pinch the neck.
- Tape the balloon to the straw. Let go.
- Try a small balloon, then a big one. Then tape a scrap of paper on as cargo.
The science
Air rushes backward out of the neck. That push is thrust. The balloon moves forward. Extra paper is extra mass, so the same push does less.
Try this next. Play the rocket game and change the fuel.