At the beginning of a new day, Li Chen led the children to exercise, more than ten children were led by an adult to run Pengcheng, it has become the morning of Pengcheng, the people are very accustomed to a scenery, not that no one thinks these people are very strange, but over time it has been strange.

When I came back from exercise, Li Chen was so beautiful that I took a cold shower, sure enough, it was still good in summer, I could take a cold shower after exercising in summer, and I had to boil good water in winter, even if it was not too hot, it was a trouble. There is also hair, Li Chen really wants to learn from those monks, and cut off the hair happily, or cut it short.

But in ancient times, this was a perverse act, except for a bhikshu, you could shave your head, and you could cut off three thousand threads of trouble, and it was very strange for ordinary people, both men and women, to have short hair, and although many times they had to be coiled up, but you just couldn't cut it short. Obviously, it is very troublesome to wash your hair, and it takes more water to wash long hair, and it is troublesome to dry it.

No wonder everyone doesn't like to take a bath, take a bath and boil water, pick up water, and dry your hair after washing, ten are bored. It's still good in summer, wash it with water, dry it a little, and let him dry it naturally, which saves a lot of effort.

Thinking of this, Li Chen regretted a little, when he left the Longevity Temple, he should have cut his hair, and then said that he was dedicated to the Buddha, although he was not a monk, but he shaved his ambition. yes, if you think about it, it doesn't seem to work.

I'm going to talk to you about physics today. After rinsing, Li Chen got his hair and put on a brand-new summer coat, which was given by Xiaohong, one of the customs of the Dragon Boat Festival, is to give each other daily clothing and accessories.

This is true from the people to the emperor. The emperor will reward his subordinates on the Dragon Boat Festival.

During the Sui Dynasty, Emperor Yang of the Sui Dynasty gave hundreds of officials tortoiseshell hairpin crowns during the Dragon Boat Festival, and Tang Taizong also gave civil and military officials belts, civil officials black tortoiseshell belts, and military attachés black silver belts.

In the eighteenth year of Zhenguan, there is a record of sending a fan, and Tang Taizong gave the eldest grandson Wuji and Yang Shidao the "flying white fan" with the inscription of the imperial pen. Due to the emperor's advocacy, the Dragon Boat Festival gave fans to the wind, and there was a lively "fan market" around the Dragon Boat Festival to sell fans, these fans are also called plague fans.

Physics is the truth of natural things. After getting dressed, it was time for the official class, and today he was going to teach physics. Li Chen doesn't understand why it's called physics, anyway, it makes sense, 'Everything you can see when you open your eyes has a reason.' Physics is about exploring these things. ’

For example, why the sun rises in the east and sets in the west, I speak to you, and why can you hear it. Have you ever wondered why? Uncle You told you that the story of Hou Yi shooting the sun, saying that the sun is a three-legged golden black bird, in fact, that is a myth. ’

Of course, it's not that all myths are wrong, but in reality, have you ever seen that kind of bird? No, don't talk about the three-legged crow, have you ever seen a creature that can live in fire, or a living creature with fire all over its body? ’

Physics is about finding out what things exist, first observing them, and then trying to understand them. Even, we have to use and control them. Li Chen was talking endlessly, when suddenly a voice interrupted him.

'Sir, is it possible for us to control the rise and fall of the sun?' A small voice interrupted him, Li Chen looked over unhappily, this is a newly adopted child, originally planned to let a few children not be completely tied to the puppet show, he recruited a few more, but then the monks were coming, Li Chen simply let the monks take over, and all the children will take classes as a priority in the future.

'Ah Mao, next time you want to ask a question, remember to raise your hand. After a little accusation, Li Chen answered his question, "First of all, you have to understand what the sun is, if you don't understand the sun, and you still think that the sun is a three-legged golden black bird, then you can't control him for the rest of your life." It is unlikely to control the sun in the 22nd century, but Li Chen did not answer truthfully, it is a good thing to have a problem, and it is not good to pour cold water on them.

'Uncle. Ah Xiang raised his hand, was stared at by Li Chen, and said, "Sir, what is the sun?" Isn't the sun just a big fireball that keeps fusing its cores? Although he doesn't fully understand the principle, Li Chen also knows it.

'Well, what do you think the sun is?' Li Chen didn't answer the rhetorical question, "The sun is a big fireball, otherwise it wouldn't be so far away and still feel the heat." Fat Ball replied with a raised hand.

'Yes, yes, yes, it's hot, the sun must be a big fireball. The puppy stuck out his tongue in response, and several other children echoed.

It's true to say that the sun is a fireball, but what does he burn with such a big fireball? Have you ever thought about why you can bring light and heat to everyone like this every day? Li Chen smiled and said, "Moreover, you say that he is a fireball, because he can emit light and heat, so every day in the stove, there will be firewood, is that also the sun?" ’

I understand that the sun is the incarnation of the Lord of the Stove, so it will always emit light and heat. Ergou clapped his hands and shouted, this answer made Li Chen stroke his forehead, this answer was even more unreliable than just now.

'Make bold assumptions and be careful to verify. Continue not to discourage the enthusiasm of children, Li Chen said this famous saying, "Physics needs imagination, bold imagination, but be careful to verify." Stay safe. Li Chen finally added such a sentence.

We can't explore the sun, in fact, everything starts with observation, and today we don't talk about the sun, let's talk about water. Well, I know you're going to want to look at the sun. He knows what the children are thinking when they have eyes.

'Observe the sun, because the sun will be dazzling, and if you look at it for a long time, it will hurt your eyes, and you have to find a way to lower the light, how to lower it? Think for yourselves, let's start with a lesson on water today. After talking for a long time, Li Chen finally entered the topic.

'Water has three variations, liquid, gaseous and solid. In fact, everything has three changes, but you can't see it. Water is the easiest thing we pay attention to. ’

Let's talk about the three states of water, the liquid state is the water we see, the kind that will flow, we can all call it the liquid state. Solid, you know, is ice. The gaseous state is water vapor, and when you boil water in winter, don't you see white heat coming out of the pot? That's the gaseous state of water. When it rises high in the sky, it turns into a cloud. ’

'Wow!'. When the children heard this, they were amazed, "Sir, do you say that there are clouds in the sky and all water?" This time, Mao Mao knew to raise his hand.

Of course, if you want proof, it's that there are clouds before the rain. There are dark clouds in the sky, and it is about to rain. Moreover, when boiling water in winter, when you open the lid of the pot, in addition to the water vapor, are there any water droplets on the lid? How did this drop come about? ’

The children suddenly realized that this was physics. Yes, they can see these things normally, but no one thinks deeply about why. It turned out that physics was all around us, and Mao Mao's eyes were even more excited.

"Okay, with all that said, let's have some fun and just let you see how the water changes." Li Chen bent down, lifted a basin of water, and put it on the table. Then pour in something, then wave your hand and signal the children to come and see.

'Wow! Wow!. ''Frozen?'' ''Is this true?'' Under the attention of the children, something happened that slowly condensed in the basin. After Li Chen then threw more things into the basin, the ice cubes formed more and faster.

'Oh my God, it's real ice. Maomao reached out and grabbed a piece of ice, his eyes widened in surprise, "Sir, are you a god?" On a hot day, you throw a little thing in your hand and the water freezes. Although the eyes are wide, but usually Mao Mao is small eyes, and the eyes are still slightly smaller than ordinary people.

'Nonsense. Li Chen tapped his head, "This is physics." No touching. When the fat ball saw the ice, he grabbed it and wanted to stuff it into his mouth, his movements were extremely fast, not at all like he usually swallowed slowly, fortunately, Li Chen had already paid attention, and he had already guessed that the fat ball had to act, and he used a faster action than him to knock the ice down.

It's going to be dead, and though it freezes into ice, it's not to be eaten. Li Chen taught Fat Ball a lesson, "Then what should I do, isn't this ice?" Why can't you eat it. ’

You don't want to think about it, if you can eat ice made in this way, then your uncle and I have really become immortals, and they all say that this is a physical phenomenon. ''Uncle, you just threw a lot of things in, is it that effect that makes the water freeze?'' Ah Xiang asked.

'Yes, Ah Xiang still cares. Li Chen clapped his hands and smiled, "You can all try it, this is physics, this is the spirit of inquiry, we need to understand why, and then let more people follow such a method to repeat a thing." ’

Li Chen gave saltpeter to the other children, and the children were so excited that they began to try, got a small basin of water, and then threw the saltpeter into it, and they could see thin ice flowers on the water.

'Well, this ice has something that can't be eaten, and it's not like we haven't made it. Fat Ball was so excited that he experimented for a while, and then remembered that the ice cube was inedible, and muttered in frustration, "I have a way." Mao Mao's eyes rolled and he thought of a way.

"Uncle, this ice can be eaten. Maomao said excitedly. Mao Mao took a copper basin, put water in it, and then put it in the center of the basin, added nitrate, and saw that the surface of the basin slowly froze, and ice chips appeared in the copper basin.

That's right, so you're ready to eat. Li Chen nodded with satisfaction, not because there was ice to eat, but because they were happy that they were willing to use their brains.

In fact, seriously speaking, it is rumored that the use of saltpeter to condense ice, this method to obtain ice in the summer, is not only available in modern times, the Chinese seem to be far away in the Tang Dynasty, and some people in Shu did this. However, it is clear that it has not been rolled out on a large scale. Of course, Li Chen doesn't want to promote it on a large scale, for now, it's better to be the treasure of the Paradise Town store first.

It's not fun to just eat ice. Seeing the fat ball's salivating face, Li Chen said with a smile, "When the time comes, Uncle will get more delicious ice products, just eating ice will not taste good." Now, move on to the lesson. ’

Next, Li Chen explained a lot of lessons with the help of water, and the children also listened with high interest, what water has to be refracted in the water, and used the friction copper basin grip to make a sound to cause the water surface to vibrate, so that the children can see what sound waves are.

The next day, Li Chen officially let them make a large amount of ice, and at the same time taught them how to use ice to play tricks, and at the same time, Paradise also officially launched ice cubes.