Shrinking a quarter down to half its size sounds like a magic trick, but there’s nothing magic about this experiment highlighted by Physics Girl Dianna Cowern. In the video above spotted by Nerdist, she explains the remarkable physics at play when a coin is at the center of a powerful electromagnet.
The rig featured in the demonstration is powered by a 160-pound capacitor capable of charging up to 8000 volts. For a little perspective, that’s similar to the amount of power delivered by some electric fences.
As the machine sends its current through a copper coil, a magnetic field is created inside it. The effects of this field can be seen when there’s a quarter at the coil’s center. The magnetic field grows stronger as the current increases, and a field forms inside the quarter itself that reaches an intensity of nearly 26.5 million watts—equivalent to about 22,080 toasters.
The pressure of the electric and magnetic fields pushes the coin evenly into itself from all sides. The result is a shrunken coin and a coil that’s been blown to smithereens—which is one of the many reasons why this is an experiment you should not try at home. If you’re looking for a DIY magnet project that’s more appropriate for home tinkerers, Cowern has also demonstrated how magnetic fields can be used to build an electric train.
All images courtesy of YouTube
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