Have you ever looked at a quarter and thought, “wow, I just wish this was a little smaller?”
Well, the folks over at Physics Girl have put together an explainer video with electric performers Arc Attack on how to do just that. They shrink coins down using super-strong magnetic fields made from super-high electric currents.
The process works by charging a capacitor (basically a giant battery) to around 8,000 volts, and then passing that electricity as a current through a coil surrounding a quarter.
Thanks to the laws of physics, the electricity creates a magnetic field that passes parallel to the loops of the coil and into the quarter. The magnetic field creates a current that flows around the quarter, causing the coin to experience inward forces and scrunch up. The copper coil experiences an outward force and explodes in a puff of smoke.
All of this is about as dangerous as it sounds; the current in the copper coil is around 50,000 amps, which Physics Girl Dianna Cowern explains is about the current in a lightning bolt. The coil and coin sit under a steel box to protect onlookers from copper shrapnel flying everywhere. You can watch the video below.