One of the biggest reasons I do this blog is because of Simon and his brilliant but simple way of explaining things. His recent post is worthy of its own feature story. This could be said of his other comments as well
Magnetic fields are inherently conservative,
Mark – magnetic fields are inherently conservative, so basically you get back exactly the energy you put into them and thus magnet motors (as usually understood) will not produce continuous energy out but only return most of the energy you put in to start them running. What they can do, though, is provide a directionality to where things will go – they can change momentum in a loss-free manner. Like electrostatic fields, gravity and nuclear forces (all conservative) they can be used to sort random directions into a single direction, and thus make random-direction kinetic energy into a unidirectional stream that we can then use.
I’ll be explaining this at more length in the next article, and maybe this time I’ll manage to explain things well-enough that a few more people will understand the dance of energy-transfers and momentum-transfers that can be de-randomised by correct use of the force-fields we already know about. Although the principle that things become more random is easily-demonstrated and applies to most situations, in the presence of a force-field it is modified and becomes anisotropic. In most cases this anisotropy is irrelevant and we don’t notice it, but with certain selected cases it can become both very obvious and useful – for example with a solar panel where an inbuilt electrical field makes the electrons go one way and the holes the other and thus gives us unidirectional electrical power from random-direction input photons. I’ll explain how a magnetic field can be similarly used to provide a preferred direction to electrons. Gravity obviously de-randomises interactions as well, since otherwise we wouldn’t see the stars in the sky (and wouldn’t be here to discuss it, either). I can’t see a way of using nuclear forces this way, though, since it’s not a long-range force relative to the scale of the atoms.
Beating the system
As far as I can tell, the engineering required to “beat the system” is beyond most back-shed experimenters’ facilities, since the scale required is of the order of microns or nanometers down to atomic for some things, so requires some special kit which is somewhat expensive and hard to make. Putting a few magnets in a special arrangement and expecting it to just turn on its own just isn’t going to do anything – you need to think about what random energy can be redirected by the system and why it will happen.
As far as we know, we cannot make or destroy energy. That also means that there is energy all around us, but we can’t use it because it is going in random directions. Our methods of “producing energy” thus involve either turning mass into energy and utilising the directionality of that random energy when it moves to an area of lower energy-density (the hot to cold direction) to get some work done, or in finding some directional energy (wind, waves etc.) and tapping it to get some directional energy to do work. There have been a few systems that change heat energy directly into electrical energy, but they have been at a low power-level and thus not useful in practical terms. Fairly soon we should have some devices that do this at a useful level of power.