What You Need:
- Adult helper
- Hard-boiled egg
- Glass bottle with opening slightly smaller than egg (apple cider or juice bottles work well)
What You Do:
- Hard boil an egg by placing the egg in a pot of cool water so the water entirely covers the egg and bring the water to a boil on high heat. You may want to hard boil several eggs at a time so you can do the trick more than once.
- Once the water comes to a boil turn the heat off, but don't take the pot off the stove yet. After about 10 minutes, remove the pot from the stove and place the pot and egg under cold running water for a few minutes. Let the egg cool.
- Remove the egg from the water and help your child peel the shell.
- Have your child place the egg on the opening of the bottle. Point out that the egg will not simply fall into the bottle. Tell him that despite appearances, it is possible to get this egg into the bottle in one piece.
- Take over duties and light two matches. Quickly drop them into the bottle. Have your child quickly place the egg on top of the bottle, wait a few seconds, and watch the egg drop into the bottle.
How it works:
This mind-blowing egg experiment is all about pressure. When you drop matches into the bottle, the air heats up. As the heated air expands, some of it escapes from the bottle. When the flames go out, the air inside the bottle cools and contracts and the egg on the bottle creates a seal. The pressure inside the bottle is now less than the pressure outside the bottle, and because nature trends toward all things being equal, the egg is forced into the bottle. To get the egg back out, you'll have to reheat the bottle. As the bottle warms up the increased air pressure will force the egg back out.