This question already has an answer here:
Obviously, a perpetuum mobile isn't possible by any law in physics, because energy can't be "created" or "destroyed", only transformed. This said, I've had an idea for a perpetuum mobile and can't seem to find my mistake (I'm actually very close to building and trying it).
Here's the plan:
Take a piece of wood and attach its upper end to a screw so it can swing like a pendulum. Then, attach a magnetic metal at the lower end of the wood. Now, place two magnets at each side of the pendulum, so that at the maximum amplitude, the metal will barely touch the magnets and will swing back, due to its weight. Now, in my head, if you give the pendulum a little impulse, it will swing up in one direction and get attracted by the magnet just a tiny bit. Thus, on the "way back", it will have a slightly higher amplitude. So it swings to the other side, closer to the magnet, which will pull the pendulum a bit more upwards, thus increasing the amplitude furthermore. This could theoretically go on and the pendulum will never stop, it will actually gain more momentum at the start.
So the conditions are:
- The Metal must be heavy enough so it doesn't stick to the magnets
- The Metal must be magnetic enough so that we gain amplitude instead of losing it each swing
And that's basically it. I am aware that the construction couldn't work, but struggle to find where I made my mistake. Anyways, if it does work and you guys build it before I do: I want 50% of all profits and want you to name it Perpenduluum Mobile :D