[Jazzman53]

I've heard that magnets retain practically all of their magnetic strength indefinitely, so long as they are not heated beyond a certain critical temperature (?)  Assuming that is so, how is it that those  little magnets sticking on my refrigerator door, which have been there for years now, are not violating the law of conservation of energy??  It could be argued that those magnets are just sitting there, not actually doing any work per the strict definition of "work" (moving a mass) so the law is not violated.  On the flip side, those magnets certainly have their own mass and they've been resisting the pull of gravity by not falling off the fridge door for all this time.  Doesn't it have to take some effort (energy) to for those magnets to resist gravity indefinitely (?)  And if the magnets' strength isn't being diminished, where does that energy come from?   Am I nuts or what?   

[GBB]

I've heard that magnets retain . . . their strength . . . so long as they are not heated beyond a critical temperature (?) 

how is it that those  little magnets sticking on my refrigerator door, which have been there for years now, are not violating the law of conservation of energy??

Doesn't it . . . take some effort (energy) for those magnets to resist gravity indefinitely (?)   

Am I nuts or what?   

The critical temperature where magnets lose their magnetism is known as the Curie temperature, after Pierre Curie - husband of Marie Curie.

It doesn't take any extra work for a magnet to stick to your refrigerator, although it did take energy to create the magnet initially. It had to be heated above its Curie temperature in the presence of a magnetic field and then cooled so that its magnetic dipoles stay aligned.  Once it's been magnetized, it will stick to your refrigerator as long as the magnetic force of the magnet is stronger than the force of gravity. It takes work to pull it off of the refrigerator, not to leave it there.

As to your final question, I'm too polite to answer that one. 

 

[decal]

Am I nuts or what?

I don't know if you're nuts but you must be incredibly bored!!

[Jazzman53]

It doesn't take any extra work for a magnet to stick to your refrigerator, although it did take energy to create the magnet initially.

I think of the mystery as this analogy:  If I hold a weight, keeping it from falling to the floor, I must expend effort to do that and when I become too exhausted to resist the pull of gravity on that weight, it falls to the floor.  My mind might say that I am expending no work in holding the weight because I am not actually moving any mass but I am quite sure my body would disagree.  Why would it not require any effort by the magnet to keep the weight from falling to the floor?  For me the implication is that the magnet indeed expends effort to hold the weight; thus, it must continually renew strength by drawing energy from some deeper level energetic source.  Otherwise, we get something for nothing.  For me, the "no work" explanation just seems untenable, even if I have no other explanation.             

[Jazzman53]

OK... I confess to smoking too much weed in my youth but I don't think I'm nuts 

[JohnR]

The magnet would have done work to pull itself towards the door, and you would have to do work to remove it from the door. But while it's there, there's no change in energy i.e. no work done.