Eggs ins and outs

Follow these instructions to trap an egg in a bottle and learn about air pressure.

• 29 May 2006 | Updated 14 October 2011

• What you need 
• What to do 
• What's happening 

Caution: This activity involves fire. You must have an adult present, plus water and other safety equipment that the adult feels is needed. Make sure no flammable items are nearby.

What you need

To do this activity you will need to gather:

• a hard boiled egg (boiled for 15-20 minutes) that has been allowed to cool
• a glass bottle or jar with an opening at the top a couple of millimetres smaller than the egg
• some newspaper
• matches or a lighter
• a sink to do the activity on
• an adult helper.

What to do

1. Peel the shell off the hard boiled egg.
2. Place the pointy end of the egg in the neck of the glass bottle or jar.
3. Scrunch up a piece of paper and light it then lift the egg up and carefully (but quickly) put the burning paper into the bottle and replace the egg.

What's happening

Thwump - the egg gets sucked into the bottle.

The burning paper causes the air inside the bottle to expand, pushing some of it out of the bottle. When the paper goes out, the air cools and contracts. The air pressure outside the bottle is greater and the egg is 'pushed' into the bottle.

To get the egg back out of the bottle, wash the ashes out of the bottle. Turn it upside down and position the egg with the pointy end back in the opening. Take a deep breath and blow in. Continue to hold the bottle upside down, wait and watch.

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