Watch a Powerful Electromagnet Shrink a Quarter to Half Its Size

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.

[h/t Nerdist]

All images courtesy of YouTube

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© 2017 USPS
Pop Culture
Speedy Delivery: Mister Rogers Will Get His Own Stamp in 2018
© 2017 USPS
© 2017 USPS

USPS 2018 Mister Rogers stamp
© 2017 USPS

After weeks of mailing out this year’s holiday cards, postage might be the last thing you want to think about. But the U.S. Postal Service has just given us a sneak peek at the many iconic people, places, and things that will be commemorated with their own stamps in 2018, and one in particular has us excited to send out a few birthday cards: Mister Rogers.

In celebration of the 50th anniversary of Mister Rogers’ Neighborhood, Fred Rogers’s groundbreaking PBS series that the USPS says “inspired and educated young viewers with warmth, sensitivity, and honesty,” the mail service shared a mockup of what the final stamp may look like. On it, Rogers—decked out in one of his trademark colorful cardigans (all of which were hand-knitted by his mom, by the way)—smiles for the camera alongside King Friday XIII, ruler of the Neighborhood of Make-Believe.

Though no official release date for Fred’s forever stamp has been given, Mister Rogers is just one of many legendary figures whose visages will grace a piece of postage in 2018. Singer/activist Lena Horne will be the 41st figure to appear as part of the USPS’s Black Heritage series, while former Beatle John Lennon will be the face of the newest Music Icons collection. Sally Ride, the first American woman in space, will also be honored.

Can You Spot the Christmas Pudding?

Whether it’s a sheep hanging out with Santa Claus or a panda bear hiding among some snowmen, regular Mental Floss readers know that hidden picture brainteasers are one of our favorite things. And the optical experts at have released a delicious one, just in time for Christmas. Somewhere in the midst of all these holiday-themed goodies above, there’s a holiday pudding just waiting to be discovered. Can you spot it? Your time starts … now.

If you give up, or are the kind of person who reads the last page of a book before the first one and just wants to know the answer, scroll down to see where it’s hiding.



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