Me and a few friends started to argue about magnets. Of course we know there are the laws of thermodynamics that basically say you cannot generate energy from nothing.
But what of magnets? If i stick a magnet to the fridge it must be generating at least enough energy to not fall down due to gravity.
Where is this energy coming from? Should it not like run out of energy sometime?
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The best analogy I can think of is a hill and gravity. If you have a generator on your bike just engage it and coast down the hill–> FREE ENERGY!
But now what? You’re at the bottom of the hill. How do you get more energy. No problem, ride the bike back up the hill. –> NOT SO FREE ENERGY.
In fact you’ve expended at least as much energy pushing yourself, the bike, and the generator back up the hill. Gravity is a force, and you can get energy from things being pulled by gravity (think hydroelectric dams), but it only works while the thing is going down. Once it’s down, the only way to get it back up is to put energy into it. Hydroelectric dams using falling water for power, but they’re basically indirect solar energy plants because the sun provided the energy to evaporate the water so it could end up raining onto the higher elevations.
Now to magnets. They provide the force, like gravity, and you can get energy by the motion of two magnets either being pulled together, or repelling each other. Just like gravity however, it only works once, then you either have to magnets stuck together or two magnets that have pushed each other apart. You need to put energy in to get them back into their original position.
The magnet on the fridge is producing a force, but without motion, there is no energy being created or consumed. The important fact here is that force and energy are two different things.
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