A magnetic cannon is a chain reaction device. It is built in a series of stages, each containing a magnet, a spacer, and a projectile. To start the chain reaction, a steel ball is released, which accelerates towards the first stage magnet. When it strikes the magnet, its energy is transfered through the magnet and spacer into the projectile which speeds off toward the next stage. The process repeats until the last projectile leaves the end of the device. The more stages an accelerator has, and the more powerful the magnets are at each stage, the faster the ball bearing will leave the final stage. This four-stage device features powerful rare-earth magnets, steel ball bearings, and 22cm firing trough.