Equipment
1 egg
1 pan of water
1 empty bottle with wide neck
Matches
Small piece of newspaper
Step 1
Bring the water in the pan to the boil.
Gently (ie using a spoon!) place egg in water. If it cracks then put a few drops of vinegar in the water. This will prevent the egg white from leaking out too much.
Get the water to simmer, and simmer the egg for about 15 minutes.
Pour the boiling water away, and run cold water over the egg for a few minutes to cool it.
When the egg is cool, tap it all over using the pan. Then, remove all the shell. You are now ready for the experiment!
Step 2
Place the egg pointy side down on the rim of the bottle. The opening of the bottle should be small enough to stop the egg falling through, but not less than about 2/3 size of the egg. I found a food bottle, such as the stir-fry sauces or smaller bottles of mayonnaise were about the right size.
Lift the egg up
Light the small bit of paper, or just drop a lit match into the bottle
Quickly replace the egg
What should happen?
The egg should be sucked through the bottle opening into the bottle. If it doesn’t then you may need to experiment with the type of bottle neck, increase the bottle volume size, or adjust how much paper to light in the bottle.
How does it work?
Well, when anything burns, a chemical reaction takes place. This is;
Fuel + Oxygen → Carbon dioxide + Water + HEAT
(n.b. the equation above is for complete combustion. In reality, combustion is never perfect and you get more products, such as soot which you may see).
During the reaction, the combustion is using up oxygen in the bottle. Heat is given out in exchange for this. Therefore, the total amount of air in the bottle decreases, as the egg is preventing any more air from entering.
This causes a pressure differential, where the air inside the bottle is at a lower pressure to the air outside. Physics is now at work! The higher pressure area (outside the bottle) is pushing on the egg so much that it is forced into the bottle.
Extend the experiment
Here are some ideas to try;
- How else could you get the egg out of the bottle (without breaking the bottle!)
- What is the smallest size bottle neck your egg will fit through?
- What is the smallest size bottle volume that you can get the experiment to succeed with?
(Harder) How could you work out what the percentage of oxygen in air is, using this experiment? |
