Colm Fitzpatrick
Children’s Corner
Is it possible to fit a boiled egg through the neck of a glass bottle without it being harmed? Most people would answer that such a feat is impossible, but with science on your side this tiny miracle is easily doable!
To perform this curious experiment, place an egg (or multiple eggs if you want the whole family to take part) in a pot of boiling water for around 20 minutes. Make sure you have a parent or responsible adult to help you as there is risk of being scalded. Once the time is up, empty the boiling water into the sink and then pour cold water into the pot to cool the egg. Once cold, peel the shell off – if you swirl the egg around in a cup of water, it will be much easier to peel.
Grab a glass bottle and rub the inside edge of the bottle mouth with vegetable oil for lubrication. Take the peeled egg and place it on top of the bottle neck to make sure it doesn’t fall in; the egg should be slightly larger than the bottle neck so use an appropriate bottle like a milk bottle.
Next comes the dangerous part: Take the egg off the bottle and set it to one side. Light two or three matches and carefully place them into the bottle and quickly replace the egg. If you’re not fast enough, the matches will extinguish and the experiment won’t work. However, if done correctly, you will see the egg begin to wiggle in the bottle mouth and then it will get sucked right in. Amazingly, the egg won’t break or fall apart and should remain completely in tact.
So what is the mysterious force pulling the egg inside? The answer is something that you might recognise from the weather forecast – air pressure. The burning match made the air in the bottle expand and get hot. This hot air makes the egg wobble as it tries to escape. When the match goes out the air in the bottle cools down, takes up less space and creates low pressure. The contrast between high pressure outside the bottle and low inside causes the egg to get sucked inside!
It’s also possible to get the egg out again. To do this you need to increase the pressure inside the bottle so turn it upside down and tilt it so the egg is sitting in the mouth. Blow into the neck of the bottle, this forces more air into it increasing the pressure inside causing the egg to pop out. Be careful during this process, as the egg could hit you in the face!
There are many other fun science experiments out there that you can do to learn about the world and how it works.