Kidoloo
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Balloon Rocket on a String

A straw, a string across the room, and a balloon that fires along it.

For ages5y - 12y
Time available30 min
Prep6 min
Mess
Noise
YouI will set it up, then step back

Five minutes to build, and they will launch it thirty times.

What you need

  • a balloon
  • a drinking straw
  • string
  • tape

How to do it

  1. Thread a long string through a straw and tie it tautly between two chairs.
  2. Blow up a balloon and pinch the neck closed without tying it.
  3. Tape the balloon to the straw.
  4. Let go and watch it travel along the string.
  5. Measure how far it goes, then try a bigger or smaller inflation and compare.

Why this is good for them

This is action and reaction made visible, and children immediately want to know why it goes backwards relative to the air escaping. Varying the inflation and measuring the distance turns a demonstration into an experiment they run themselves.

Adapting by age

4 to 5 yearsYou build it, they launch it and count how many chairs it passes.
11 to 12 yearsTest string angle, balloon shape and straw length as separate variables.

Keep it safe

Burst balloon fragments are a choking hazard. Clear every piece and keep away from under-threes. Check for latex allergies.

Cleanup tip

Untie the string and keep the straw for next time.

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