Our Bunny Bottle can be used together with some boiled eggs to examine the power of air pressure and see why air can push objects around due to pressure differences. In our Looney Lab episode, we also show you some variations on how to do this experiment (including liquid nitrogen).
Try out our mini-experiment below this one as well or more in our Bright Spark guides to go ALL OUT! How egg-citing is THAT?
A large glass bottle with a wide mouth (we used a 500mL conical flask)
Several hard boiled eggs that have been peeled
Some cooking oil
Several strips of paper (2cm x 10cm….. size not crucial)
– Matches means you need an adult to help you
– Check the glass bottle that it has no cracks in it
– Careful not to drop glass bottle on the ground.
1. Rub some oil on the outside of the de-shelled egg. (This makes it slippery and reduces friction between the glass and egg).
1. Place the glass bottle on the table and peeled egg next to it. The adult lights the paper and once burning, places it into the bottle.
2. As the paper is still burning inside the bottle, place the egg on the mouth of the bottle and watch carefully. (you may see some air ‘push’ past the egg and cause it to wobble a little).
4. What happened? Can you get the egg back out using pressure?
Of course you can.
Getting Egg back out! (without smashing it into ‘scrabbled egg!)
5. Tip the bottle upside down so that the egg is in the mouth of the bottle.
Now blow into the bottle as hard as you can (big bad wolf).
It should come out of the bottle.
Did you like this? Would you like to take it further? Why not try our ‘Collective’ Bright Spark guides. These are packs contain multiple experiment guides on a ‘collective’ theme which include:
- detailed explanation of the science,
- suggestions for modifications on this experiment,
- how to set it up more scientifically (variables etc),
- perfect for homeschooling or those wanting to ‘Go All the Way!’
Check out our product section.
Many people think the egg is ‘sucked’ into the bottle……….Nope!
You may remember that air expands as it is heated and contracts when it is cooled. The reason that is the case is that the air molecules get more energy (and thus move faster) when heated. When they move faster they take up more space (called volume) and increase the pressure of the container.
This means that the hot air from the match moves upwards and pushes the egg out of the way a little to move outside of the bottle.
The air inside the bottle now starts to cool. As the air cools it contracts (taking up less volume) and the pressure decreases inside the bottle. The outside air pressure is now higher compared to the air inside the bottle and tries to moves INSIDE the bottle.
As the air moves towards the inside of the bottle it pushes the egg inside the bottle!
Getting the egg out of the bottle!
We can use air pressure again to push the egg out of the bottle. We just need to make the air inside the bottle HIGHER than the air pressure outside the bottle.
By blowing hard, the air moves past the sides of the egg and increases the pressure inside the bottle. This pushes the egg out of the bottle.
Kinetic Particle Theory: This is a theory to explain properties of solids, liquids and gases. It states that all matter is made of vibrating particles called atoms.
Expansion: When atoms get energy, their vibrations increase causing them to move more and take up more space. They therefore ‘expand’.
Contraction: As matter is cooled it looses energy and the particle (atoms) reduce how much they vibrate and take up less space. Hence they ‘contract’ or get smaller in volume.