On 2001-10-24 15:19, Wiley wrote:
On 2001-10-24 09:15, Phobos wrote:
Diamagnetism has been widely reported in science journals and is well understood. It is believed that you could "magnetise" a human being so that he would levitate in a magnetic field in the same way.
However diamagnetism does not look too promising as a alternative means of space propulsion. The claim by this new company is that what they have produced can be used as a means of propulsion.
There are three different types of magnetism: ferromagnetism, diamagnetism, and paramagnetism. Ferromagnetism is what we usually think of when think of magnetism. Iron is the typically example (surprise! it's even called ferro
magnetism) and the atoms have permanent dipole moments.
In paramagnetism the dipole moments align with an external magnetic field and produce and attractive force. In diamagnetism, the dipoles align opposite
to the magnetic field, and produce a repulsive force. Diamagnetism and paramagnetism are much weaker than ferromagnetism, about 6-10 orders of magnitude weaker. Usually paramagnetism is stronger than diamagnetism.
Diamagnetic levitation is quite real, but can it be used pratically? Since ferromagnetism and paramagnetism are attractive forces and are significantly stronger than diamagnetism, whatever is levitated must comprises diagmagnetic materials only. In other words iron and steel are right out. Some plastics may be diamagnetic, I don't know.