How do magnets work? Seriously.

[pErvinalia]

TANSTAAFL... It's always one of those acronyms that never sticks in my mind. ALWAYS have to google it.

[Xamonas Chegwé]

TANSTAAFL... It's always one of those acronyms that never sticks in my mind. ALWAYS have to google it.

I'm like that with Acronym too.


Abbreviated Contextual Reminder Obliquely Nudges Your Memory - Who could remember that mouthful?

[Pappa]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

The energy has already been expended in aligning the innards of the magnet so that all of its whatsits are pointing in the same direction.

There is a total CHUNK of energy in an aligned whatsit - like fucking SHITLOADS! But pulling and pushing stuff around with the power of your innards causes them to slowly unalign - it might seem like a magnet just stays sticky FOREVAH - but it doesn't - it's just that the electromagnetic force is pretty damn HUGE compared to gravity (1036 times as MASSIVE!) and a little goes a long way. Stick an anvil to a magnet and dangle it - sooner or later the magneticisticism will run out and the anvil will fall directly onto the head of any passing coyote - but it will take a while - go have a cup of coffee and come back later... Magnetism can be preserved by inducing it with electrickery, or some shit, in which case, as long as you keep jamming volts into it, your anvil will hang there until the universe heat-death catches up with it - but energy free lunches only exist in fairy tales.

A while back on RDF, I asked the simple question, "Do magnets run out?". I was asking because I assumed what you just said was the case. This neatly explains how magnets exert a force, which has nothing to do with the kinetic energy used to move two magnets close together, and is nothing like gravitational potential energy either.
Unfortunately on RDF I was ridiculed and told flatly that, no, magnets don't run out. It was one of the reasons I stopped posting in the serious threads there.

[rainbow]

Magnets have to exist, or we wouldn't exist to observe magnets.

[JimC]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

The energy has already been expended in aligning the innards of the magnet so that all of its whatsits are pointing in the same direction.

There is a total CHUNK of energy in an aligned whatsit - like fucking SHITLOADS! But pulling and pushing stuff around with the power of your innards causes them to slowly unalign - it might seem like a magnet just stays sticky FOREVAH - but it doesn't - it's just that the electromagnetic force is pretty damn HUGE compared to gravity (1036 times as MASSIVE!) and a little goes a long way. Stick an anvil to a magnet and dangle it - sooner or later the magneticisticism will run out and the anvil will fall directly onto the head of any passing coyote - but it will take a while - go have a cup of coffee and come back later... Magnetism can be preserved by inducing it with electrickery, or some shit, in which case, as long as you keep jamming volts into it, your anvil will hang there until the universe heat-death catches up with it - but energy free lunches only exist in fairy tales.

A while back on RDF, I asked the simple question, "Do magnets run out?". I was asking because I assumed what you just said was the case. This neatly explains how magnets exert a force, which has nothing to do with the kinetic energy used to move two magnets close together, and is nothing like gravitational potential energy either.
Unfortunately on RDF I was ridiculed and told flatly that, no, magnets don't run out. It was one of the reasons I stopped posting in the serious threads there.

Pappa, permanent magnets are like a spring. They don't "run out", they simply (when acting in pairs) store and release energy from outside their system...

[pErvinalia]

It's exactly like gravitational potential energy, Pappa.

[rainbow]

Yes, exactly like, but completely different.

[pErvinalia]

Exactly the same principle.

[rainbow]

Knicker elastic as well.

[pErvinalia]

Yeah, that elastic field is an amazing phenomenon...

[FBM]

I think it's the metal wot's attracting the magnets. Not the other way 'round. When the magnet is lighter than the metal, it's the magnet that moves.

[rainbow]

We shall never know, just as whether the 'lastic moves the knickers, or the other way round.

[Mysturji]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

It's no "freer" than gravity.
Seriously. Think about it.
If we could get magnetism and gravity working together (or maybe against each other) we could make a perpetual motion machine.
Of course, you couldn't take any energy out of it or it would stop moving, but it would make a great desktop ornament. (It'd give Newton's cradle a kick in the balls, that's for sure)

[hackenslash]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

No, they do expend energy and undergo entropy, as do all processes, including those involving boson exchange. Over time, a magnet will emit all the photons stored in its electromagnetic field and it will no longer be magnetic. This is a slow process, as the actual energy emitted is extremely small, as per E=mc2 (photons have no rest mass; their energy is in their wavelength). A higher energy magnet isn't emitting more photons, it's emitting photons with a shorter wavelength, thus higher energy and a greater force.

Photons are polarised, as the recent findings from BICEP2 show quite nicely. When they're all aligned in the same direction, i.e., with the same polarity, the magnets each absorb photons from the other, generating an area of negative pressure between them that draws them together. When they are aligned in opposite directions, the emitted photons 'bounce off', generating an area of positive pressure between them.

This is a massive simplifcation, but it is, in essence, how magnets work.

[Robert_S]

Feynman didn't help much.