Originally performed in 1922, the Stern-Gerlach experiment provided scientists with the first hint that quantum particles had an unrecognized kind of magnetism. In the experiment, researchers fired silver atoms through a magnetic field and measured where they landed on a screen. While an ordinary magnet could end up anywhere (depending on its strength and orientation), the atoms only showed up at two discrete spots. Below is a simulation of the experiment that allows you to choose what to send through the two magnets from source to target.