We will build a magnetic accelerator (also called a gauss rifle) with acceleration stages and little metal balls.
We will use the gauss rifle to learn more about physics and momentum by trying to see how far a ball being launched by a gauss rifle will fly depending on how many magnetic acceleration stages are in the setup and the metal balls initial velocity.
The kinetic energy within the metal balls are transferred to the magnets on the ruler
As Kinetic energy powers up through the metal balls they start to move to the magnets hitting faster and faster transferring all the Kinect energy to the last ball making it speed off the ruler to hit the place you pointed the rifle at.