Air is a lot stronger than you think! With enough air pressure, you can squeeze an egg in a bottle. Whoa!

All you need is a bowl of hot water, a bowl of ice cold water, a hard-boiled egg, and a glass bottle. This experiment works best with a milk bottle or any glass bottle that has a wide neck and an opening a little bit smaller than the tip of the egg. We used a Promised Land milk bottle for this experiment.

Watch the experiment in action:

So how is that possible?

When you put the bottle in the bowl of hot water, the air inside the bottle is heated. Hot air expands, which means the air molecules (tiny particles that make up air) spread out, increasing air pressure.

Next, when you put the bottle in the bowl of cold water, the molecules come closer together because cold air contracts. This causes air pressure to start decreasing. As air pressure decreases, the greater air pressure outside the bottle pushes the egg into the bottle.