The content of mathematics is not profound, especially at this stage, it is still within the scope of 'understanding', such as the understanding of numbers, the understanding of simple geometric figures, and so on.

In addition, combined with the addition and subtraction of fingers, they were taught to add and subtract within 20.

After that, the physics class is relatively complicated.

Unlike several other courses, 'Physics' is only the first class, and it will be taught by Blade Tooth himself for the time being.

--------

"I heard it's the Tooth Witch Doctor, the youngest one."

"The one who created the word?"

"Yes, yes, and the 'mathematics' we learned before, it seems that he researched it."

"Ahh The sinners who ruined our childhood. ”

"Come on, if it weren't for the Tooth Witch Doctor, you wouldn't even know what 'destruction' and 'childhood' would be now."

"Haha, that's what I said."

The little ones who re-entered the class waited in the noise caused by the sound of communicating with each other.

It didn't take long for Bladetooth to arrive, and after placing the 'teaching aids' made of large and small clay tablets in his hand on the side of the podium, he didn't say anything more, and went straight to the lesson.

"The words 'matter' and 'reason', I think you should all know them, after all, I said hello to your literacy teacher."

"So in this first class, let's talk directly about what 'physics' is really a study of."

He took the huge clay tablet he had prepared from the side and set it up on a wooden support.

The clay tablets were engraved with the words 'How matter evolves?' and were carefully smeared with charcoal to make sure all the trolls could see clearly.

"The question of 'how matter evolves' may seem like a big one, but it's a good place to start."

"First, we're going to look at the meaning of each word."

"What is 'matter'? Let's start by assuming that all matter is made up of smaller 'elements', so if we grasp the arrangement of each 'element' in space, is it the same as mastering this matter? Therefore, matter can be extended to the position of the 'element' in space, which we will first denote by 'x'. ”

With that, he bent down and took a square clay tablet engraved with an 'x', rubbed the thread with the wood fiber tied to it, and hung it on the short vertical pole reserved on the bracket.

"Let's look at 'evolution', we often say 'how was yesterday', 'how is today', 'how is the day after tomorrow', this is a kind of evolution, talking about a relationship of change over time. Essentially, this is a temporal dependency, which we denote as 'f(t)', which is used to represent the dependence of the amount of change f on time t. Well, it's a 'function' that you'll only get into in the future, but for now, just know that there's going on. ”

"Let's go back to the question itself, that is, 'evolution of matter' can be expressed as 'x(t)' when taken together."

"Next, let's see, what is the 'how'."

He walked around the podium, stood in front of the little trolls, and said,

"Now, here I am...."

After that, he slowly walked to the middle of the 'classroom' and said again,

"At this moment, I was standing here again, about 20 meters in between, and I counted in my heart for about 5 seconds."

"That is, I walked 20 meters in five seconds."

"So, can we know where I'm going in the second second? If I keep walking, where will I be in 30 seconds? ”

"Well, actually, we can know that with the constant speed of my travel, I walked 8 meters in the second and 120 meters in the 30th second."

"How do I know? Why is it possible to calculate the position 3 seconds ago and even the future position 30 seconds later when we know the starting point, the time it takes, and the distance traveled? ”

"Going back to the question of 'how matter evolves', in fact, the thinking we just had is one of the manifestations of 'how', which is asking how this x(t) came about, and where this x should change at different moments."

"And 'the change of x at different moments' can be extended to 'motion', in other words, the question is 'how does motion happen?' 'On what basis is it?' ''How do you know where it's going next?'' ’。 ”

。。。。。。

After all, Blade Tooth is not a teacher, and it is still a little difficult for him to grasp the difficulty and accuracy of the content.

At this moment, I can only retell the knowledge in my mind in a way that I feel is easy to understand.

In short, after a class, it's hard to say how effective it is, anyway, some little guys are at a loss and don't seem to understand anything, and some are thoughtful.

"What do you think, old witch doctor?"

After class, Bladetooth met the old witch doctor who had been listening in the corner and asked.

"I'm very inspired, especially in 'mastering the arrangement of elements in space', and our use of magic today, does it feel like it can also be interpreted with this?"

"Well, I have similar thoughts, but as I told you before, we have too few means to observe the 'microcosm', and we can only classify it as 'conjecture' for the time being."

"Well, it's good to be cautious. However, I don't think the children understand much, isn't the content too in-depth? ”

"No way, after all, the age span is too big, and it's normal to have differences in understanding. However, I don't want them to understand, anyway, let's turn around the boat, first follow this rhythm for a while, and then organize an 'exam', depending on the situation, and then decide whether to divert or simply reduce the difficulty. ”

"It's okay, when the time comes, you can pick out a group of good learners, and cultivate them first."

"Yes, in the next class, I'm going to start teaching them formally with 'Uniform Linear Motion'."

"Okay, it's good for you to grasp it, but you can't relax your own research, come to us three old guys at any time if you need to."

"Okay."

After a brief exchange, the two trolls went their separate ways.

Back in the 'lab', Bladetooth began his research again.

Due to the previous 'simple' storage methods, the development has been declared a failure.

This time, he plans to come up with something that has been subconsciously denied earlier due to the lack of energy, metals, and other conditions.

'Let's sort out the working principle of the refrigerator in the previous life.... No electricity, no metal mines, no means of processing.... Although it may not be of much use to sort it out.... I hope I can at least expand my thinking. ’

With that in mind, he began to try to recall the structure of the refrigerator in his home when he was a child.

It seems that on the back of an old-fashioned refrigerator, there is a metal fence that emits heat.... Combined with the low temperature environment inside the refrigerator, let's think about it together... It seems easy to conclude how it works...'

'Transferring the heat from the inside to the fence by some means and dissipating it .... That's right, right? ’

Is it called heat exchange? Or is there another name? ’

'Well, it doesn't matter what it's called, think about the means of transferring heat....'

'Heat dissipation.... If it is a human body, part of the heat dissipation should be carried out by evaporating sweat. ’

'Switching to a refrigerator means that the refrigeration zone absorbs heat and the heat dissipation zone dissipates heat... Water evaporation can take away the heat of the human body, so the evaporation step should occur in the refrigeration area, not the subconscious heat dissipation area. ’

'From this, it can be deduced that it should be a cryogenic liquid flowing into the refrigeration zone to facilitate the removal of heat..'

'Liquid evaporation and endothermy, is there such a phenomenon?' So, it's not necessarily about taking away the heat, maybe the process of transformation itself is about consuming heat... For the time being, I just need to know that this is the result. ’

But how do you do it when it's cold? ’

'Think about it, is there any principle.... On the plateau, the boiling point of water decreases .... It seems that the key is still low pressure? ’

In other words, what flows into the refrigeration zone may be a liquid at low temperature and low pressure. ’

'By evaporating it in the refrigeration zone, taking away or dissipating heat?' ’

"What flows out of the refrigeration zone is low-pressure steam? ... What about temperature? The refrigeration area is not a stove, whether it takes away the heat or consumes the heat.... Intuitively, I don't think the temperature will rise too much at this point, right? ’

'Where does the heat come from the radiator?' ’

Let's assume that the heat of the radiator has nothing to do with the temperature brought out of the cooling zone... On this premise, it is logical to see where the low-pressure steam is going to go...'

First of all, the refrigerator doesn't have an external liquid inlet... Meaning inside... Remember it's called 'refrigerant', right? ’

This means that the refrigerant inside is recycled... That is to say, the low-temperature, low-pressure liquid flowing into the refrigeration zone is homologous to the low-pressure gas flowing out there..'

'Then in the middle, it must go through one or several processes before it can be reused....'

'Let me think, gas turns into liquid.... Pressure? Compressed steam? If so... The liquid state will absorb heat when it changes to the gaseous state, so will the gaseous state change to the liquid state and release the heat? Low-temperature and low-pressure steam will be compressed into high-temperature and high-pressure liquids. ’

So, what the radiator dissipates is actually the heat released when the refrigerant vapor is compressed into a liquid state? Well, that makes a lot more sense. ’

The place where vapor compression takes place is called the compression zone. ’

'Sort it out, compression zone - change high temperature and high pressure liquid - heat dissipation zone - change low temperature and low pressure liquid - refrigeration area - change low temperature and low pressure gas - compression area.... And so on and so forth...'

"No, the span from high-temperature and high-pressure liquids to low-temperature and low-pressure liquids is too large, and the heat dissipation area should not have this ability.... So, there should be one more step in between. ’

'This step should play a role in cooling and lowering blood pressure....'

When the pressure drops, the boiling point of the liquid decreases, and when the boiling point drops, it is easy to evaporate, and evaporation can consume heat, so it will naturally cool down... So, low air pressure = easy evaporation = cooling .... Is it just about how to lower blood pressure? ’

'Buck....'