Physical laws are just inferences based upon years of scientific observations and experiments, which are repeated repeatedly under different conditions to arrive at inferences that can easily be accepted around the world. In all of the physical laws, there is undoubtedly no principle more sacred than the Second Law of Thermodynamics. Thermodynamics deals with the relationship between heat and energy. It is a study of how thermal energy converts to and from other forms, as well as how thermal energy affects matter. Classical thermodynamics has just a few laws. The first states that energy can be conserved. The second state that heat moves from hot to cold is the law of thermodynamics. This is usually expressed in terms of entropy.
Entropy must increase in any change process. While the disorder is commonly equated to entropy, the Austrian physicist Ludwig Boltzmann defined it more clearly as a number that measures the number and types of microstates within a system. This means how many ways the particles can be organized in an equivalent way. The second law shows why change can occur in the first place. The classical laws are able to be reversed at the particle level. But, the second law says that any change must be made in a way to increase entropy. This is widely believed to impose directionality on time. The view that time flows from past to present is based on the fact that the universe began, for unknown reasons, at a low level of entropy and is now heading towards an ever greater level. This means that heat will eventually spread evenly and there will no driving force to cause further change. It’s depressing prospect scientists have called the heat-death of the universe.
The energy that is produced from heat is thermal energy. This heat is created by tiny particles moving within an object. The more these particles move, then the more heat will be generated. Thermodynamics has no concern about how these energy changes are performed. It is based only on the state of the energy that undergoes the transformation. It is important that Thermodynamics does not deal with macroscopic science. This means that it focuses on the bulk system and not the molecular composition of matter.
Arthur Eddington, British Astronomist, wrote in 1928 his book The Nature of the Physical World that “if someone points you out to the contrary about your pet theory of the world — then so much the worst for Maxwell’s equations.” Maxwell’s equations are a group of coupled partial differential equations which, along with the Lorentz force laws, form the basis of classical electromagnetism as well as classical optics. In other words, Maxwell’s equations, a group of four equations that describe electric and magnetic fields as well as how they relate to one another are four equations. They demonstrate that electric and magnetic fields are two manifestations of the same phenomenon.
Physicists are still troubled by something regarding the second law. Some don’t believe we know it well or that its foundations can be trusted. Although it’s called law, it’s usually considered probabilistic. It specifies that the outcome in any process will be most probable. This basically means that the outcome can only be determined if enough numbers are involved.
A number of groups independent from each other might have created the second law from the basic principles of quantum mechanics. Some suspect that they have directionality or irreversibility embedded in them at the highest level. The second law does not result from classical probabilities. It is due to quantum effects such as entanglement. It results from quantum systems sharing information, as well as from fundamental quantum principles that determine what is allowed and what cannot. An increase in entropy is more than the most likely result of the change. It is a logical consequence of the most fundamental resource known to us — the quantum resource, information.
However, thermodynamics did not help to make better engines and machinery. Instead, thermodynamics became a pillar of modern Physics, providing the guidelines that govern all change.
