A Tabletop Demonstration Railgun
Railguns operate according to the principle that when a current is at right angles to a magnetic
field, a force is produced at a right angle to the current and the magnetic field.
Figure 1: F = I l x B
A railgun consists of two rails with a projectile in between. A current is passed down one rail,
through the projectile, and back through the other rail. A magnetic field is set up around the
currents in the rails, in the same way that a magnetic field is set up around any wire carrying
Figure 2 : Induced Magnetic Field from a Current Carrying Wire
The current in the projectile is at a right angle to the magnetic field between the rails, which
sets up a force acting to push the projectile away from the current source.
Figure 3 : Force Acting on Projectile