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How do you demagnetize an object ?

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

So theoretically lowering the temperature lowers the magnetic field/Ferro-magnetic charge.

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).

Originally posted by grey fox
So theoretically lowering the temperature lowers the magnetic field/Ferro-magnetic charge.

yes

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."

http://www.newton.dep.anl.gov/askasci/phy00/phy00146.htm

Originally posted by Mindship
"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."

http://www.newton.dep.anl.gov/askasci/phy00/phy00146.htm

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.

true...so decreasing it will increase magnetism but increasing temp will only make it...and i quote from your link..."less magnetic"

but as you say...only at extremes

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

Originally posted by Mindship
"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."

http://www.newton.dep.anl.gov/askasci/phy00/phy00146.htm

Less magnetism, not NO magnetism, just because one webpage doesnt state about absolute zero, it doesnt mean its not true...

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 above which a ferromagnetic material loses its permanent magnetism."
http://scienceworld.wolfram.com/physics/CurieTemperature.html

"Temperature at which a material loses its magnetic properties."
http://www.allmagnetics.com/glossary.htm

"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/phenomena/curie_temperature.html

Basic physics. Have a nice day.

Throw it in a volcano.

gud idea

i made i peice of steel a magnet in plumbing, i directed the heat so as to alince the atoms point one way, it was wai c00l

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?

Originally posted by Mindship
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 above which a ferromagnetic material loses its permanent magnetism."
http://scienceworld.wolfram.com/physics/CurieTemperature.html

"Temperature at which a material loses its magnetic properties."
http://www.allmagnetics.com/glossary.htm

"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/phenomena/curie_temperature.html

Basic physics. Have a nice day.

thank god i dont do physics

strike physics, strike math...

Originally posted by PVS
strike physics, strike math...

luckily i'm A grade biology, chemistry, law, crime scene investigation, explosives, forensic computing and statistics

Originally posted by jaden101
luckily i'm A grade biology, chemistry, law, crime scene investigation, explosives, forensic computing and statistics

cookie?

Originally posted by PVS
cookie?

is it choc chip?

Also, improperly storing the object with another magnetized object, with north pole with north and south with south, can disorder the magnetic domain.

Originally posted by Wonderer
Why would you want to de-magnetise a magnet anyway?

Exactly the question I wanna be asnwered first..

Why did you ask such question?

Rub down your computer with it.