What you need for this experiment is a hard boiled egg, a few birthday candles and a bottle.
- Place the candles into the egg and then light them.
- Now place the bottle over the candles.
- Watch as the egg gets sucked completely into the bottle.
The air in the atmosphere exerts atmospheric pressure. When the candles are lit, the air inside the bottle got hotter and expanded. Some of the air escaped from the bottle.
When the flame went out, the air inside the bottle cooled down and contracted so the air pressure decreased considerably.
This meant the atmospheric pressure outside the bottle was greater than that inside the bottle. This sucked the egg into the bottle.