Gadgets that rely on magnetic levitation, also known as magnetic hovering, to suspend various objects in the air are not hard to find these days, but how do they work? Why is it not possible to suspend one magnet over another without the top magnet inevitably making contact with the bottom magnet? The answer is … science!
A Gentle Introduction to Magnetism
As you know, ferrite magnets (composed of ferric oxide combined chemically with one or more additional metallic elements) and neodymium magnets (made from an alloy of neodymium, iron, and boron) are useful for much more things than securing important documents and notes to your whiteboard.
Being permanent magnets, ferrite magnets and neodymium magnets have two magnetic poles: one South pole and one North pole. The names of the two poles come from a time before Google Maps and GPS navigation, when compasses provided the most reliable method for finding the right way to a destination.
Both the South pole as well as the North pole create magnetic fields, which typically manifest as either a force that attracts or repels other magnets, depending on their polarity. The same magnetic polarities create a repulsive force while opposing magnetic polarities create an attraction force.
Magnetic Levitation at Home
If you have two magnets of roughly the same size, you can try a little experiment with magnetic levitation.
Place one magnet on a solid surface and position another magnet directly above it so that the magnets are facing each other with the same poles. If you hold the top magnet, you should feel the repulsive force counteracting the weight force. Notice that as soon as you let go of the top magnet, it falls after being suspended in the air only for a couple of milliseconds.
Does this little experiment prove that floating magnets are a scam? Far from it! It demonstrates the problem described in Earnshaw’s theorem, which states that it is not possible to achieve static levitation using any combination of fixed magnets and electric charges.