Launcher

How

1. Pull the rope to lift the ball to the upper position of the tube.
2. Then, release the rope and observe what happens at the top of the second tube.

Why

When the large ball falls, it rapidly compresses the air trapped between it and the smaller ball inside the tubes. As the air expands, it propels the smaller ball upward.

Fun facts

A similiar principle is used in internal combustion engines. There, compressed air and fuel explode, generating propulsion. Volcanic eruptions, on the other hand, are a natural example of gas being ejected under high pressure!

In some sports, such as paintball or air-powered guns, compressed air is used to launch projectiles at high speed.