only theoretically by freezing a magnet to absolute zero (which has never been achieved) and thus stopping the flow of electrons through the magnet can you stop its magnetic field
Actually, heat will demagnetize a magnet: enough thermal energy "loosens up" the electron alignment. The level of heat required is called the Curie temperature (or the Neel temperature).
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lowering the temperature of anything reduces the movement of atoms within it...but only at absolute zero does that movement stop altogether
absolute zero is recorded as zero Kelvin...the lowest recorded temp was i believe 3 picoKelvin which 0.00000000003 K pretty close to absolute zero but not quite
"Cooling a metal can make the motion within less random, thus allowing more atoms to line up with each other. This increases the magnetic field of the material. On the other hand, making a magnet very hot will cause more random motion, resulting in less allignment of molecules and less magnetism."
while the line of motion of electrons in a magnet can increase the magnetic power...it is the motion of the electrons that is the basis of the magnetic force in the first place....at absolute zero all motion within and between atoms stops....if there is no electron motion there is no magnetic force
but like i say...its only theoretical because absolute zero has never been reached
Being an extreme condition, absolute zero (theoretically) affects many properties of matter, not just magnetism. Might as well point out that a temperature of 1,000,000oF (another extreme) will demagnetize an object, too.
You also wrote...
With all due respect, this is false, as the Curie temperature shows.
Regardless, w/o going to an unattainable extreme, Heat demonstrably decreases a magnetic field, Cold increases it.
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it also depends how you percieve it...put a magnet inside a superconductor and it wont be magnetic as superconductors dont allow magnetic fields...but technically the magnet still works
i thought running electricity through it would do the trick. or else i have that backwards, and electricity magnetises the metal. which is probably more likely, considering electromagnetism
Everyone is taking the "less" vs "no" magnetism wording a bit too literally. Suffice to say: the more you heat up a magnet, the greater the reduction until, at some point, you get No Magnetism. That is what the Curie temperature does.
"The temperature for a given ferromagnetic substance above which it becomes merely paramagnetic." ((Paramagnetic means weakly attracted to magnetic fields, or, displaying magnetic properties only in the presence of another magnetic field.)) http://www.exploratorium.edu/xref/p...emperature.html
Basic physics. Have a nice day.
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Last edited by Mindship on Jun 25th, 2006 at 08:46 PM
Magnets also lose their magnetism by wear and tear, or you can hit it hard against any hard surface a few times. Why would you want to de-magnetise a magnet anyway?
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Jun 25th, 2006 11:49 AM
