19th December 2005 - 05:06 AM
I got to thinking and I relised that magnets are natures over unity devices. I meanI have this little neodymium magnet and when I hold another magnet a foot away from it the magnet on the table will jump to my hand. So therefore the magnet is moving without the application of kinetic energy. It is therefore putting out more power (the power needed to move) than it is recieving (none at all).
19th December 2005 - 05:52 AM
Keep thinking - you will realize energy conservation remains. Magnets exert a magnetic field (we're talking about electromagnetic waves here), which loses power over time as entropy rises i.e. magnetic domains disintegrate.
19th December 2005 - 01:23 PM
Pull them apart - work done by snelson = x Joules
Wizz click (that's them coming back together) - work done by magnets = x Joules
Pull them apart again - work done by snelson = x Joules
Wizz click (again) - work done by magnets = x Joules
No free lunch, unfortunately.
19th December 2005 - 05:03 PM
This issue is somewhat deceptive because, if I purchase magnet A and magnet B from different stores, and in fact they were mined from different places, then we think of them as never having been pulled apart in the first place.
But if we remember that, between every pair of charged particles in the universe, there is a certain amount of potential energy stored in the EM field, and that this energy grows or shrinks based on distance and the charge relation (+/+, -/-, or +/-), and then remember that, according to the Big Bang theory, all matter began smooshed into a tiny space, then all becomes clear...
When the "Bang" happened, all the particles shot away from each other with incredible kinetic energy. Between every pair of like-charged particles, there was an initially huge amount of EM potential, which is converted to an extra kinetic boost as the particles separate. For every pair of differently-charged particles the reverse happened: a bit of the initial kinetic energy is converted to potential, stored in the EM field, as they separate.
Obviously, I've stated this pretty much exclusively in terms of the electric field alone. But the electric and magnetic fields are just different facets of the same phenomena, and so they are intextricably linked and related. Though the relationships are a bit more complex, in magnetic terms, the general logic applies the same. The potential energy existing between two magnets did not spontaneously appear when the magnets were mined, or formed, or whatever. It is an aggregate behavior, arising from the combined traits of constituent particles. And the relationships between those particles have been there since the beginning of the universe.
Sometimes, even for apparently mundane phenomena, you have to take into account a bigger picture than just the here and now, in order to get a self-consistent explanation.
10th January 2012 - 01:56 AM