Floating in Copper
See this exhibit in the relocated and reinvented Launchpad - the Science Museum's most popular hands-on, brains-on gallery – when it opens on the 24th November.
Making a magnet float is mesmerising, so Floating in Copper is one of Launchpad’s most captivating exhibits.
A large piece of copper has been split down the middle, with a strong magnet placed inside the split. Moving another magnet above the copper creates eddy currents in it, which make the magnet float in midair. With practice you might even figure out how to make it flip!
How does it work? The magnet floats thanks to eddy currents - tiny electric currents that flow in a metal which is moving through a magnetic field. These little currents create more magnetic fields that oppose the original one, leading to some gravity-defying effects.