Are perpetual motion machines possible or not? Free energy?

Most of us might have had this idea, that magnets attract each other in opposite poles, so why can’t we use this to create free energy. Like placing a magnet or a metal in a car and attach the other magnet with a rod or something and place it in front of the car that keeps them attract each other. With this idea, we can move the car without any energy, forever. A perpetual motion machine is a device that is supposed to work indefinitely without any external energy source. Imagine a windmill that produced the breeze it needed to keep rotating or a light bulb whose glow provided its own electricity. These devices have captured many inventers’ imaginations because they could transform our relationship with energy. It sounds cool right? But there is only one problem, it won’t work.

Bhaskara’s wheel -The oldest perpetual motion machine

In countless instances in history, people have claimed that they have made a perpetual motion machine. Around 1159 A.D. a mathematician called Bhaskara the learned sketched a design for a wheel containing curved reservoirs of mercury. He reasoned that as the wheels spun, the mercury would flow to the bottom of each reservoir, leaving one side of the wheel perpetually heavier than the other. The imbalance would keep the wheel turning forever. Bhaskara’s drawing was one of the earliest designs for a perpetual motion machine. And more people have claimed that they made a perpetual motion machine, like Zimara’s self blowing windmill in the1500s, the capillary bowl where capillary action forces the water upwards, the oxford electric bell, which takes back and forth due to charge repulsion, and so on. In fact the US patent office stopped granting patents for perpetual motion machines without a working prototype.

Why perpetual motion machines won’t work?

Ideas of perpetual motion machine all violate one or more fundamental laws of thermodynamics. These laws describe the relationship between different forms of energy. The first law of thermodynamics says that “Energy neither be created nor be destroyed”. You can’t get out more energy than you put in. that rules out a useful perpetual motion machine right away because a machine could only ever produce as much as it consumed. There wouldn’t be any leftover energy to power a car or charge a phone. But what if you just wanted the machine to keep itself moving? Let’s take the Bhaskara’s wheel, the moving parts that make one side of the wheel heavier also shift its center of mass downward below the axle. With a low center of mass, the wheel just swings back and forth like a pendulum and will stop. In the 17th century, Robert Boyle came up with an idea for a self watering pot. He theorized that capillary action, the attraction between liquids and surfaces that pulls water through thin tubes, might keep the water cycling around the bowl. But if the capillary action is strong enough to overcome gravity and draw the water up, it would also prevent it from falling back into the bowl.

John Keely’s perpetual motion machine

For each of these machines to keep moving, they had to create some extra energy to nudge the system past its stopping point, breaking the first law of thermodynamics. There are ones that seems to keep moving, but in reality, they invariably turn out to be drawing energy from some external source. Even if engineers could design a machine that didn’t violate the first law of thermodynamics, it still wouldn’t work in the real world because of the second law. The second law of thermodynamics tells us that energy tends to spread out through processes like friction, heating. Any real machine would have moving parts or interactions with air or liquid molecules that would generate tiny amount of friction and heat, even in a vacuum. That heat is energy escaping, and it would keep leeching out, reducing the energy available to move the system itself until the machine inevitably stopped. Like I said about the idea of a car with magnets, the magnets in it won’t able to move the car. Even if the magnet is so powerful to move the car, the friction came into action and will eventually stops the car. So these two laws of thermodynamics will destroy every idea for perpetual motion. With these, we can conclude that perpetual motion machines are impossible.