Is a perpetual motion machine really impossible?

2022-05-01 0 By

Since ancient times, in order to maintain survival, human beings invented and manufactured all kinds of machinery, such as inclined plane, pulley, lever and so on.Later, with the progress of social material civilization, human beings made many machines.With machines, man has created rich material wealth and spiritual wealth.However, no matter how much improvement is made to the machine, it is found that any machine or machine must be operated by external forces, including human, animal, wind and modern production of electricity, water, chemical, nuclear forces and so on.Moreover, with any machine it is possible only to reduce the strength and change the direction of the force, but not to reduce the work done by it; that is to say, to make the machine do as much work as possible, one must supply it with at least a corresponding amount of energy, or even more.Once the supply is stopped, no machine can run forever.”Make the horse run, and make the horse not eat grass” approach, this is certainly not done in real life.Historically, some people have envisioned two kinds of perpetual motion machines.The first perpetual motion machine is completely isolated from the outside world, relying on the machine’s own energy to run round and round.However, no matter how detailed and thoughtful the design scheme, or even “painstaking”, it ended in failure in the actual production.The reason is that, without any external force, the friction resistance in the process of machine operation can not be eliminated in any case, they will only consume the energy of the machine itself, and the machine can not run eventually.There is a universal physical law in nature — the first law of thermodynamics, which is the expression of the law of conservation of energy in heat.It tells us that the energy of a body can neither be created nor lost in the absence of any external energy supply.When there is inevitable friction resistance, once the energy of the machine is “out of ammunition” in dealing with friction resistance, it is impossible to run down, and the perpetual motion machine has become a fantasy.The second type of perpetual motion machine is not completely isolated from the outside world, but only unilaterally from an external heat source to absorb heat, and can go round and round forever.It is also impossible to build such a machine.This is because any machine must have two channels to exchange heat with the outside world to keep running.The machine draws energy from one channel, partly to do the work it is required to do, and inevitably from another channel.The engine of a car is a classic example.Without gasoline, the car engine is “out of food”, it is impossible to start, but only gasoline, there is no exhaust channel, the car is also impossible to move forever.Through a lot of experiments, physicists have concluded the second law of thermodynamics, which tells people that the transformation of energy is directional.It is impossible for human beings to create a perpetual motion machine against this direction.In daily life, people can rub their hands continuously to make their palms hot, which is the process of heat.However, the heat obtained by the car engine from gasoline is not all used to start the car, and some of the heat will certainly “escape”, which shows that the heat can not be all converted into work, which is the unidirectional between heat and work.Also, if you put a glass of hot water and a glass of cold water next to each other and only allow them to transfer heat to each other, the result must be that the hot water will cool down and the cold water will warm up until the two glasses of water are at the same temperature.No one has ever seen hot water automatically take more heat from cold water to continue heating, and cold water to further cooling phenomenon.That’s the direction of heat transfer.In short, perpetual motion machines of the first and second kinds are impossible to make, because they violate the general laws of energy change in nature, which have been proved by numerous experiments!