Wet science joke!

Wet science joke!

How does this trick work?

This experiment makes a great joke. Try it on your parents or a friend!

What you need:

  • Plastic water bottle
  • Pin
  • Sellotape
  • Water

How to:

Have a look at this video:

Try it! Be prepared for a bit of leakage, but don't worry.

  1. Use the pin to make several small holes in the bottle. Keep them roughly at the same level around the bottom of the bottle.
  2. Use sellotape to cover up the holes in the bottle.
  3. Fill the bottle with water and screw the lid on.
  4. Take the tape off the bottle.

If you're playing a joke on someone, leave the bottle on a table. Watch what happens when they try to pick it up!

What's happening?

When the cap is on the bottle, the pressure inside the bottle is equal to the pressure outside the bottle. This means that the water stays inside the bottle, even though there are holes in the bottle.

If somebody squeezes the bottle or takes the cap off, the pressure inside the bottle is greater than the pressure outside the bottle. This causes water to squirt out!

Curriculum information