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Do magnets lose their magnatism over time?

 
 
Reply Mon 30 Jan, 2012 09:12 pm
Do magnets lose their magnatism over time? Also, it takes energy to counter the effect of gravity, right? So if magnets don't lose their magnatism, how long could a magnet of the same polarity float in the air over another, forever?
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Type: Question • Score: 3 • Views: 7,653 • Replies: 10
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Butrflynet
 
  2  
Reply Mon 30 Jan, 2012 09:38 pm
@buckaroobanzai,
http://science.howstuffworks.com/magnet.htm

Quote:
The resulting magnet's strength depends on the amount of force used to move the domains. Its permanence, or retentivity, depends on how difficult it was to encourage the domains to align. Materials that are hard to magnetize generally retain their magnetism for longer periods, while materials that are easy to magnetize often revert to their original nonmagnetic state.

You can reduce a magnet's strength or demagnetize it entirely by exposing it to a magnetic field that is aligned in the opposite direction. You can also demagnetize a material by heating it above its Curie point, or the temperature at which it loses its magnetism. The heat distorts the material and excites the magnetic particles, causing the domains to fall out of alignment.



This site has lots of graphs and diagrams that demonstrate the quote above.

http://www.coolmagnetman.com/maghow.htm

Butrflynet
 
  2  
Reply Mon 30 Jan, 2012 09:43 pm
If you want to get even more technical, this physics site has some good input for you:

http://physics.stackexchange.com/questions/8036/do-magnets-lose-their-magnetism
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BillRM
 
  0  
Reply Mon 30 Jan, 2012 09:53 pm
@buckaroobanzai,
Let see yes over prolong time magnets can decrease their magnatism depending on such factors as the material of the magnet and the surrounding temperature and so on.

No it does not need to take energy to remain at some position in the gravity field.

It take force on the object equal to the gravity field force at that point and the force can come from the walls of a building or a magnate field or air pressure or...............

To change the position of an object in a G field does take energy or yield energy for example climbing the steps in a building with a weight take energy.

Ok force and energy are not one and the same thing and you can have forces on an object and have zero energy.

Lord to explain this fully you would need to give a 101 physics course and cover such concepts as force and potential energy and that work equal force over a distance and on and on..........

Sorry you need to take out a few books that cover newton physics from the local library.
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BillRM
 
  0  
Reply Tue 31 Jan, 2012 08:15 am
@buckaroobanzai,
Footnote as a very young child my grandfather had a very very large horse shoe magnate and playing young tom Edison I warped a coil of wire around it and using a toy train transformer I demagnetiz it.

My grandfather was very unhappy when he try to used it and then yell my name for some reason!!!!
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buckaroobanzai
 
  1  
Reply Sat 4 Feb, 2012 09:58 am
@Butrflynet,
So if nothing adversely affects the magnet, will the magnet repelling an object so that it floats above it lose it's magnetism faster than a magnet not floating an object? I mean, it takes an expenditure of energy to resist the pull of gravity, right?
BillRM
 
  0  
Reply Sat 4 Feb, 2012 10:03 am
@buckaroobanzai,
Quote:
I mean, it takes an expenditure of energy to resist the pull of gravity, right?


WRONG once more it take force not energy.

A wall with an object resting on it above the ground is not expending energy to keep it there and neither is a magnate.
BillRM
 
  1  
Reply Sat 4 Feb, 2012 11:03 am
@BillRM,
Interesting is someone disagreeing with me that it take force not energy to keep an object at a given level in a G field?

Or is someone just being as asshole in voting down my posting?
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buckaroobanzai
 
  1  
Reply Sun 12 Feb, 2012 01:48 am
@BillRM,
Hmm... Okay, but isn't it gravity that's holding said object? And isn't gravity a property of matter? And isn't matter and energy one and the same? It's confounding me...
BillRM
 
  1  
Reply Mon 13 Feb, 2012 08:00 am
@buckaroobanzai,
Matter and energy is the same that however does not mean that there is any energy being used by a magnet or the magnetic field around a magnet to keep an object suspended in middle air.

A wall holding up a object is matter and it does not used any energy contain in the matter of the wall to keep an object on it at a given level above the ground.
buckaroobanzai
 
  1  
Reply Tue 14 Feb, 2012 01:24 am
@BillRM,
Good point, but I recently watched a science show and the scientist stated that the atoms/molocules of two separate objects never actually come in contact with each other because of the electromagnetic properties of said objects, good grief this is very vexing!
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