Fire a beam of electrons and it will pretty much just go in a straight line. Unless it runs into a electrostatic or magnetic field, that is, and then your beam is going to do some deflecting. This is due the electrons having a charge and thus affected by other charges or magnetics. This is a major principle an electromagnetics and the force that makes the electron beam move is known as the Lorentz Force. The Lorentz force is actually very important for many day-to-day applications. Cathode Ray tube computer monitors and TVs needed the Lorentz Force to make images – and without those you would not have LCD & LED screens of today.
Measuring the Lorentz force is always a bit tricky in physics classes, so to help professors and teachers we offer United Scientific’s Lorentz Force Demonstrator.