British Science Week: How to get an egg in a bottle
by Ailsa Harvey · 11/03/2021
Squeeze a hard-boiled egg into a bottle with the help of some smart science
1. Boil the egg
First you need to hard-boil the egg. Getting a raw egg into a bottle would be far too easy! Ask an adult to help you by boiling some water on the stove, then drop in the egg and leave it boiling for at least ten minutes.
2. Peel the shell
Once your egg has boiled and cooled, take it out of the water and carefully peel off the shell. You should be left with a rubbery egg that’s hard all the way through. If you want to try the experiment a few times, boil more eggs.
3. Use some matches
Next, find a glass bottle with a neck that’s narrower than the egg – it needs to be glass as plastic will melt. Carefully light at least three matches, and drop them into the bottle so that they don’t go out.
4. Act fast
Before the matches burn out, place the egg on the top of the bottle with the wide end up. You don’t need to push it down – just make sure the egg forms a seal around the neck of the bottle.
5. Watch it slide
The egg will start sliding into the bottle as the air pressure inside decreases and pulls it in. As it pops through, a rush of air will fill the bottle again, so the matches will probably go out.
6. Use a candle
You can also use birthday candles. Push two or three into the bottom of the egg, being careful not to break it. Then light them and place the egg on the neck with the bottle on its side.
Summary
When the egg forms a seal on the bottle the matches burn the remaining oxygen then go out. The air in the bottle cools quickly, and the volume of air decreases. This lowers the air pressure and because the air pressure outside is higher, the force overcomes the friction of the egg on the bottle neck and pulls it inside.
For more fun science activities, download your free British Science Week activity packs here: https://whf.cm/2OrCa3e
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