How do you get an unboiled egg into the bottle?

Materials:

* Hard-boiled egg (the shell needs to be removed)

* Glass bottle with a narrow neck (a standard glass milk bottle works well)

* Matches or a lighter

* Piece of paper

Instructions:

1. Prepare the egg: Carefully peel the shell off a hard-boiled egg. You want the egg to be completely naked.

2. Light the paper: Light the piece of paper on fire and drop it into the bottle.

3. Quickly place the egg on the bottle: Immediately place the egg, narrow end down, on top of the bottle's opening.

4. Watch the magic: As the paper burns, the air inside the bottle heats up, causing the air pressure to increase. When the flame goes out, the air inside the bottle cools, creating a lower pressure. This difference in pressure creates a suction that pulls the egg into the bottle.

Important Notes:

* Safety first: Be careful with fire! Always have an adult supervise this experiment.

* The size matters: Make sure the egg is slightly smaller than the bottle's opening, but big enough to create a tight seal.

* It may take a few tries: Don't be discouraged if it doesn't work right away. Experiment with the size of the paper and how quickly you place the egg on the bottle.

How it works:

This experiment demonstrates the principles of atmospheric pressure and thermal expansion. The burning paper heats the air in the bottle, causing it to expand. When the flame goes out, the air cools and contracts, reducing the pressure inside the bottle. The pressure outside the bottle is greater than the pressure inside, so the atmospheric pressure pushes the egg into the bottle!