Since magnets never stop working (unless they overheat), why don’t scientists use them to create clean energy?
Magnetism is a FORCE, not ENERGY. The two are profoundly different concepts and you’d be amazed at how many people get confused by that fact.
Forces can be generated without consuming any energy. Gravity (for example) is a force – and gravity doesn’t ever “run down” either.
When you put a book onto a table – gravity exerts a force on the book – and the table generates an equal and opposite force to stop the book from falling through the table.
Just as the gravity force never runs out – neither does the force exerted by the table.
Forces are “free”.
Energy, however is NOT free.
Energy can be thought of in many ways – but in this context, energy is “Force, moved through a distance”.
If you try to pull a fridge magnet off of the fridge – you have to use energy to move it because you’re moving the magnet (which is exerting a force) through some distance – and the energy to do that has to come from your muscles.
Once the magnet is an inch or two away from the fridge, it has some energy – the energy you put there from your muscles. This is called “potential energy”.
When you let go of the magnet – and it snaps back against the metal – the potential energy gets converted into motion (“kinetic energy”) and when the magnet hits the fridge, that gets turned into a tiny amount of heat and sound energy – which dissipates through the air and the metal of the fridge.
The magnet itself didn’t use up any internal source of energy to do that – the entire process was just energy going from one place to another.
Electrical generators move magnets around in a circle to convert mechanical energy into motion of the magnets which transfer that energy into coils of wire. But the magnetic fields of those magnets aren’t changed by doing that.
So, no – you can’t get energy from magnets unless you first put energy INTO the magnet in some way.
Credit: Steve Baker