Ma Whistle is talking about Clausius entropy, but the connotation of entropy is much more than that.

In later generations, the concept of entropy was the top of the top, and all disciplines were happy to discuss it.

The discussion of entropy in the natural sciences and philosophy has been protracted, and it has been honored as a guest in literature, film and television, and there are countless concepts and theories extended from it.

Leaving aside the discussion of other disciplines, only within the scope of physics, entropy also has three important historical stages - Clausius entropy, Boltzmann entropy, and information entropy.

Each stage of change means that human beings have a deeper understanding of the essential laws of the world.

The next thing he wants to talk about is Boltzmann entropy, which is also the most commonly discussed entropy in later generations.

As for information entropy, he doesn't plan to talk about it, after all, it's a hundred years from now, and it's a little too advanced.

"For a certain substance, the entropy of a gas is greater than that of a liquid, and the entropy of a liquid is greater than that of a solid. Is it conceivable that entropy is actually a measure of chaos and disorder? Ma Whistle said slowly.

"After all, it is obvious that a mass of matter changes from a solid to a liquid, a gas, its structure becomes more chaotic, and the particles inside move more wantonly."

The whistle paced to the blackboard and continued, "My gut or paranoia tells me that this assumption is correct...... So, is there any way to give this idea a mathematical expression? ”

Hearing this, many people felt brain-opening and amazed.

"How chaotic is the matter? How can this be expressed mathematically? "One can't help but wonder.

"Can this really be done......

Ma Whistle picked up the chalk, wrote the Boltzmann formula on the blackboard straightforwardly, and said, "Of course there is a way, and this is what the second law of thermodynamics really looks like." ”

Although the Boltzmann formula is concise, if you want people to understand it, you need to explain it.

Looking at the dazed physicists, Ma Whistle did not rush to explain the formula itself, but said: "Let's imagine a scenario like this, in a box, there are two hydrogen molecules ......"

"Molecules?" Before the words fell, there was a discussion in the audience.

At this time, people's understanding of elementary particles is extremely scarce and inconsistent.

The atomic theory is still controversial, and the molecular theory is not widely shared.

"Or atoms." Ma Whistle thought for a moment and changed his words.

"I don't agree with such a thing as an atom, I can't see or touch it, it's completely conjecture, matter should be infinitely divisible!" A physicist immediately protested, with a somewhat heated attitude.

Ma Whistle smiled: "Speculation? In my opinion, infinite divisibility is a conjecture without factual basis, when has human beings been divided infinitely? ”

"From ancient times to the present day, we have been engaged in finite divisions, and according to the principle of experience, the most reasonable assumption is that matter has a finite divisibleness."

"It is true that atoms are beyond our senses, but infinitely divisible is not only beyond the senses, but even beyond all experience, and even more ethereal."

"It's like an ant walking on a tabletop, and every step it takes is like the previous step, and it naively thinks that the wooden plane under its feet is infinitely extended, how ridiculous."

Atomism was one of the most controversial topics in the academic world at this time, and it has been debated by various schools for a long time.

In fact, the debate would continue until Einstein's time.

The tone of Ma Whistle's words was not peaceful, which aroused people's heated discussions even more.

"He's right, atomism is the truth!"

"Nonsense, Dalton's theory is simply heretical!"

"The followers of Betzerius are all @%/!"

"You scold again!"

For a moment, the scene seemed a little out of control.

Seeing this, Ma Whistle hurriedly changed the topic: "Regarding atomic theory and molecular theory, I think Brownian motion is a case worthy of attention, and I will publish a paper to elaborate on my views in the near future, and you are welcome to criticize it at that time...... As for now, that's not the topic of my presentation. ”

Fortunately, the professors were of good quality, and they didn't really let the scene get out of control, and it didn't take long for them to quiet down.

Ma Whistle drew a diagram on the blackboard and continued: "Whether it is an atom or a molecule, or some other tiny particle, does not affect my rest of the discussion, suppose there are two hydrogen atoms in the box—let's put it that way." ”

"There is no doubt that, macroscopically, there are three cases of the distribution of these two hydrogen atoms, all on the left, one on the left and one on the right, all on the right."

At the micro level, the number of states corresponding to the three is one, two, and one...... Let's draw a curve to represent it. ”

"Assuming that the probability of each microstate is equal, this curve reflects the probability of the distribution of atoms."

"Obviously, as the number of atoms increases, this curve will become narrower and narrower, and the atoms will have a greater probability of being more evenly distributed in space, which is in line with our life experience - air can spread spontaneously without contracting spontaneously, and it is almost impossible for us to encounter a situation where the air atoms are concentrated in one place and cause people to suffocate."

After the explanation, Ma Whistle brought people's attention back to the Boltzmann formula: "Now we can understand the meaning of this formula, when a system has the greatest entropy, it is in the most chaotic macroscopic state with the largest number of corresponding microstates. ”

There was silence for a moment.

Most people don't immediately understand the mystery of Boltzmann entropy.

This is also reasonable, after all, Ma Whistle has just given Clausius entropy, and many people haven't even figured out Clausius entropy.

But this is not difficult for Ma Whistle, as a teacher, he has seen this state in all his students.

His solution is simple: keep giving examples, analogies, and coming up with problems, just as engineers train artificial intelligence, and pour a lot of data into the minds of students and mark them.

This may be the only way, after all, a lot of knowledge is indescribable and can only be obtained by training. For most people, intensive trial and error and iteration are a stage that must be experienced in professional learning.

So Ma Whistle began a stormy explanation, put forward many cases in daily life, and made questions to investigate, which was completely a teacher's lecture posture.

He is fully qualified to do so, and as an excellent teacher one hundred and eighty years later, if he cannot teach these nineteenth-century predecessors, it probably only shows that mankind is a race that has not grown.

As the lecture progressed, even the professors themselves had to admit that the Indian chief with the yellow face in front of him was an impeccable mentor.

In the academic halls of today's world, every tone of his voice seems to be an echo of the ancient Greek sages.

Eventually, with the exception of a few uneducated bastard professors and physicists like Faraday, most of the audience understood the concept of Boltzmann entropy.

However, understanding does not mean agreeing.

"Do you have any questions?" Ma Whistle said, and slightly restrained the teacher's posture in order to make himself look humble, "Doubtful fellow...... Well, a friend can raise his hand. ”

As soon as he finished speaking, a man in his early thirties raised his hand, his position was relatively backward, which made him have to stand up, obviously not a senior scholar.

"What do you call it?" Ma Whistle said casually.

"George Bull." The man said.

Hearing this name, Ma Whistle couldn't help but be stunned for a moment.