Well Done Cubs

You found the secret message.

You now have a go at a hidden magic trick.

What happens when you blow up a balloon and stab it with a pin?

Of course it pops.

But what if I told you it doesn’t have to?

What you need

  • Balloon

  • Sellotape

  • Pin

Blow up the balloon and tie it off

Place a peice of sellotape on the balloon

Stab the balloon with the pin

What’s happening?

What causes a balloon to pop is called catastrophic crack propagation. This really complicated sounded phrase means that the hole in the balloon widening is what makes it pop, not the fact that air is slowly being let out. When the balloon’s hole gets bigger, it rips and eventually the balloon pops. In this experiment, the tape slow down this process.