There are quite a few neodymium magnets falling through copper pipes on the internet, but we can still understand why this demonstration video is making the rounds: it’s just so cool looking! We’ve covered the phenomenon of magnetic damping before:
When a magnetic field moves through a conductor a current called an Eddy current is induced in the conductor due to the magnetic field’s movement. The flow of electrons in the conductor creates an opposing magnetic field to the magnet which results in damping of the magnet and causes heating inside of the conductor similar to heat buildup inside of power cords. The loss of energy used to heat up the conductor is equal to the loss of kinetic energy by the magnet.
And a note of caution if you decide to try this, these magnets are not for unsupervised children. In fact, everyone should be careful:
Neodymium magnets larger than a half inch are very strong and should be handled with extreme care since they can be dangerous. It is best to stick with neodymium magnets of quarter inch diameter or less.
Want to know more? Look up Lenz’s Law and watch Veritasium’s Derek Muller demonstrate how this phenomenon is related to English scientist Michael Faraday and the first electric generator, created with a magnet and a coil of wire in 1831:
Physics! Another must-watch magnet-doing-magic-like-things-video comes from the Ri Channel: Levitating Superconductor on a Möbius strip.