Do you know what a perpetual motion machine is? It is a magical device that does not require any external energy source to function all the time. Sounds cool, right? But do they really exist? Let's take a look at some of the famous perpetual motion machine designs in history and why they all failed.
About 900 years ago, there was an Indian mathematician named Bhaskara. He came up with a wheel filled with mercury, a liquid metal. He believed that when the wheel turned, the mercury would flow to the lowest place, which would make one side of the wheel heavier than the other. He hopes that this weight difference will keep the wheels spinning forever. This was one of the earliest designs of a perpetual motion machine, but it had a fatal flaw. When the wheel turns at a certain angle, it loses its balance and falls over, like a crumbling spinning top. So, the wheel doesn't move forever, but stops after a while.
So, is there any other way to keep a machine in motion? Many inventors have tried it because they felt that a perpetual motion machine could change our lives. Imagine if you had a windmill that could generate wind on its own, or a light bulb that could emit light on its own. These devices can provide us with unlimited energy and even allow us to live forever. However, these devices all have a common problem, they all violate the rules of physics. Physics is a science that tells us how energy is converted between different forms. There is a very important principle of physics called the first law of thermodynamics. It means that energy cannot be created or destroyed, only converted. You can't get energy out of thin air, and you can't make it disappear. This means that you can't use a machine to produce more energy than you input. You can only get as much as you give. This excludes all perpetual motion machines that can provide us with additional energy, as they are all impossible.
But what if we don't need extra energy and just want a machine to move all the time? This is also not possible because there is another principle of physics called the second law of thermodynamics. What it means is that the energy is always going to be more and more dispersed and more chaotic. Any real machine will have some loss of friction or heat, which are all losses of energy. This energy gradually consumes the machine's power until it stops moving. Therefore, no machine can completely avoid the loss of energy, and no machine can be perpetually moving.
So, why are people still trying to make perpetual motion machines? Because humans are always curious and creative, we always want to explore uncharted territory. Maybe one day, we will discover some new matter or phenomenon that will make us rethink the rules of physics. Perhaps in the microcosm, there is some perpetual motion phenomenon. We can't say we'll never find a perpetual motion machine, but we can be sure that we'll never give up looking. Now, the only thing that is truly eternal is our seeking.