Why Did The Trebuchet Launch?

When you push the launching arm down, you bend the craft stick and stretch the rubber bands.

This stores elastic potential energy—energy that’s waiting to be released.

As soon as you let go, the stored energy is quickly transferred into movement. The launching arm swings upwards, pushing the projectile out of the bottle cap and into the air.

The farther and faster the launching arm moves, the more energy can be transferred to the projectile. That’s why changing parts of your trebuchet can affect how far it launches.

Scientists Say…

A trebuchet is an example of a lever—one of the six simple machines.

Levers help us move objects more easily by changing the size or direction of a force.

Your tiny trebuchet also stores elastic potential energy in the bent craft stick and stretched rubber bands. When released, this energy changes into kinetic energy, sending the projectile flying through the air.

Engineers use these same ideas when designing machines that launch, lift or move heavy objects.

Curiosity Spark

Engineers rarely stop after building their first design.

Instead, they ask questions like:

• Does a heavier projectile travel farther?

• How does a stronger elastic band change the launch?

• Does moving the launching cup make a difference?

• Which design is the most accurate as well as the most powerful?

What would you investigate next?

Related Missions

[Elastic Energy Launcher]
[Crater Makers]