Egg in a bottle science experiment

Egg in a bottle science experiment

This classic kitchen science experiment will amaze your kids.  Can you figure out why the egg gets sucked into the neck of the bottle?

What you need:

  • 1 x hard boiled egg, peeled
  • 1 x glass bottle with a wide neck (just wide enough to sit the egg in)
  • Boiled water from the kettle

Number of players:


Pour boiling water into the bottle to about a third of the way up.

Place the hard boiled egg so that it sits in the neck of the bottle.

Watch and wait. You will notice the egg gets shifted by the hot air in the bottle, this is when the hot air expands and escapes a bit.

The egg will eventually get sucked into the bottle.

Why is it so?

The hot air from the hot water expands and forces its way out of the bottle, making the egg shift around.

As the air cools inside the bottle the air contracts and takes up less room. This creates lower pressure inside the bottle than outside. The greater pressure outside the bottle forces the egg into the bottle.

Hints and tips: 

  • To get the egg back out of the bottle, tilt the bottle and blow air into it. Watch out though, because the egg will shoot out of the bottle!

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