Levitation experiments
Bismuth has the highest diamagnetic coefficient of any metal. This means that it will expel a magnetic field from its interior and so one can arrange a setup (see steam-punk rig below) in which one can levitate a rare-earth magnet --- without supplying any external energy or cooling. Basically, one creates a small stable region between two bismuth plates in which a magnetic field pulling up on a small test magnet just balances the gravitational force pulling down on that same magnet.
See also moving pictures of the Bismuth pour and the Spinning Magnet.
The raw materials
Smelting the bismuth birdshot
Close-up of smelting
Solidifying pure bismuth
The "steam-punk" rig.
Levitating magnet.
Construction :
1) obtain bismuth (e.g. gem shop)
2) melt on gas stove and pour into mold (inverted coke can)
3) once cooled file top surface as flat as possible
4) build a rig with wood and brass screws with large rare-earth magnets above the two disks
5) fine tune separation distance of disks and top magnet until you achieve liftoff.
Ralph Buchholz
18 April 2011