Explain the principle of entropy increase to the minimum.

The principle of entropy increase is that the entropy of any physical system can only increase or remain unchanged without energy being delivered to it by the outside world, and will not actively decrease.

For example, if a room is not cleaned, it will become more and more messy, so why is it getting more and more messy? The doorway here is deep. Let's do a simple demonstration. Suppose a physical system has ten particles, give one particle a speed of ten meters per second, and the other particles will not move. Intuitively, a particle with speed will distribute its speed to a stationary particle through collision. The state in which all particles move is definitely much more chaotic and entropy is higher than that in which only one particle moves. Then why do physical systems like higher entropy? According to the principle of minimum energy, the kinetic energy of particles is proportional to the square of velocity. When a particle moves at the speed of 10 meter per second, the kinetic energy is proportional to the square of 10, that is, 100, so the energy of other particles is 0, because there is no movement, the total energy of 10 particles is proportional to 100. Now the particles with velocity divide the velocity equally among other particles, so that the velocity of each particle is 1, and the kinetic energy of each particle is proportional to the square of 1, or 1. The total energy of ten particles is 10, which is 10 times smaller than the former. According to the principle of minimum energy, the system certainly likes the latter energy.

However, the law of conservation of energy has not dispelled the dream of scientists, who dream of building another perpetual motion machine, hoping that it will not violate the first law of thermodynamics and be economical and convenient. For example, this kind of heat engine can directly absorb heat from the ocean or atmosphere and convert it into mechanical work. Because the energy of the ocean and atmosphere is inexhaustible, this kind of heat engine can work endlessly and is also a perpetual motion machine.