3 levitation tricks
No magic – just physics!
Warning! This experiment involves the use of small magnets. Only under adult supervision.
- parallelepiped neodymium magnets;
- graphite plate;
- cap with valve;
- hot glue;
- frying pan;
Flying House: Make a “rug” from neodymium magnets, arranging the poles of neighboring magnets in a checkerboard pattern. Put a graphite plate on the rug: it will be suspended a few millimeters above the magnets! You can build a foam house on the resulting "flying foundation"!
Hovercraft: Hot glue a plastic cap with a valve to a CD, carefully sealing the joint. Put an inflated balloon on the valve: as soon as it starts to deflate, the CD begins to slide over the surface, hovering above it!
Levitating droplets: Heat a frying pan to a high temperature and drip water on it from a pipette: observe how the water doesn’t spread, but collects in droplets that skitter over the surface and take a long time to evaporate!
Flying House: Graphite placed in an external magnetic field is magnetized against it. This repels the graphite plate from the surface of the magnets with a force that exceeds the force of gravity. As it moves upward, away from the magnets, the force of its interaction with them decreases, and as soon as this force becomes equal to the force of gravity, the plate hovers in the air! The poles of the magnets are staggered to create a restoring force when displaced: there is a horizontal component to the interaction with the magnets in addition to a vertical one, and this keeps the plate from flying out of the boundaries of the rug. The magnets thus counterbalance each other horizontally and create a “trap” for the plate.
Hovercraft: As the balloon deflates, increased pressure arises under the CD, which lifts it off of the table. Since the CD is not in contact with the table surface, it can slide over it frictionlessly!
Levitating droplets: Upon contact with a surface with a much higher temperature than the boiling point of water, a droplet forms a vapor layer due to the instantaneous evaporation of part of it. This layer insulates the water from the hot surface, so the evaporation of the remaining droplet is slower than if it were in direct contact with the surface. In addition, due to the presence of a vapor layer, the drop is suspended above the hot surface, easily moving above it in the absence of any resistance to movement.
You can find more cool experiments in the MEL Physics subscription!