Sebald Justinus Brugmans, Michael Faraday electromagnetism |
Diamagnetism
In 1778, Sebald Justinus Brugmans, as a graduate student, found that bismuth and antimony were repelled by a magnetic field. * In 1845, Michael Faraday showed that diamagnetism was a property of matter, and all materials are either diamagnetic or paramagnetic.
Levitation
A superconductor levitates above a magnet. Push and it pushes back. Ha, ha. Look, Ma, action at a distance.
No energy expended
A pyrolytic carbon wafer floats above a permanent ferromagnet with no expenditure of energy, which makes me wonder. Have I, all these years, have I been lazy, blind, and passed over the unexpected?
What shall we call it? Michael Faraday got the term diamagnetism from William Whewell.
A ferromagnetic material can be permanently magnetized; it can have its own persistent magnetic field. Diamagnetic and paramagnetic materials get only temporary magnetic fields induced by other magnetic fields. The induced magnetic field in a diamagnetic material is in the opposite direction, so an exterior magnetic field repels it. The induced magnetic field in a paramagnetic material is in the same direction, so an exterior magnetic field attracts it.
See also in The book of science:
Readings in wikipedia: