"Pole photography?"

“What does this have to do with yin and yang?”

Zhang Zhixiang doesn't understand very well. He only knows that the shadow at noon is the shortest, and the winter solstice is the day of the year when the noon shadow is the longest. The winter solstice has just passed, so the difference should not be big.

Now the sky is clear after the snow, the sun is shining brightly, and the shadows of the bamboo poles are quite clear.

Come on.

The ancients probably also used the length of the sun's shadow to determine the two most special seasons, the winter solstice and the summer solstice, based on pole photometry...

"The shadow of the sun is the longest on the winter solstice, and the shadow of the sun is the shortest on the summer solstice. Do you know this?"

Zhang Baichuan took another bamboo pole, left a little space outside the shadow of the sun, and then used this as a radius to draw a circle in the snow. Not to mention, it was quite round.

After his son responded, Zhang Baichuan pointed at the circle on the ground and said, "This is the earth, the planet we live on."

"Well...just like an egg."

"In the theory of Huntian theory, the sun, moon and stars are all in the egg shell and egg white, and we live on the egg yolk. The sky is round and the place is in the opposite direction. In fact, the places are relative."

"Can you understand this?"

Zhang Baichuan was worried that his son would not understand such advanced astronomical knowledge, while Zhang Zhixiang was shocked that the Ming Dynasty had realized that he was living on a planet!

"I can understand..."

"Well, it's good to understand. Pangu Kaitian said that the chaos of the heaven and earth is like a chicken. Hehe, in fact, after the heaven and earth were civilized, they were also chickens. The sun, moon and stars are all supported by Qi, so they hang high in the sky."

"This is what Xuan Ye said."

"In short, Gaitian Theory, Huntian Theory, and Xuanye Theory are the three major theories of astronomy. You can understand them when you have time. Now, let's continue talking about Yin and Yang."

As he spoke, Zhang Baichuan marked 24 marks on the circle.

Pointing to the bottom, he said: "This is the winter solstice."

Pointing to the top, he said: "This is the summer solstice. There are 24 scales, corresponding to the 24 solar terms."

"If you have read the "Zhou Bi Suan Jing", it contains all the records of the length of the sun's shadow in the 24 solar terms. The winter solstice is 1 feet 3 feet 5 inches, the spring and autumn are 7 feet 5 inches 5 minutes, and the summer solstice is 1 feet 6

inches, I can’t remember the rest, but it was roughly a gradual process.”

"And during the summer solstice, at the Tropic of Cancer, which is 23 degrees 26 minutes north latitude, the sun shines directly at noon and the length of the solar shadow is zero."

"This can also be fed back to the picture."

"The sun rises in the east and sets in the west, and so do the stars."

"If you have watched the starry sky overnight, you will find that except for Polaris, all the stars in the entire starry sky are rotating counterclockwise from west to east."

"The sky is spinning, and the earth is spinning too."

"So, on the left side of the winter solstice is Xiaohan, and this is how the solar terms are arranged."

"The winter solstice is the time when the yin energy between heaven and earth is the heaviest, so at this time the yin is generated in the heart and the yang is generated at the end. When it comes to the summer solstice, the yang energy is at its strongest, so the next step is that the yang is generated in the heart and the yin is generated at the end. From then on

Starting from the summer solstice, the length of the sun’s shadow needs to be drawn from the circumference.”

"We draw the lengths of the shadows of the 24 solar terms in turn and connect them..."

"Look, the Tai Chi diagram is formed."

Zhang Zhixiang's eyes widened. He had never thought that Tai Chi diagram was not derived from philosophy, but was derived from scientific induction such as the length of the sun's shadow!

"Hey, are you surprised?"

Zhang Baichuan was very satisfied with his son's expression, which gave him a great sense of accomplishment as a father. Although he was a scholar who wrote sloppy eight-part essays, he read a lot of miscellaneous books.

He sat down again, drank some wine, and sang opera.

Zhang Baichuan was only over thirty, and he still had a young man's style. Although the Zhang family was not a landowner, they were still a wealthy family. They owned a shop in Shangqing Town and had a hundred acres of fertile land.

If your family has more money, you will naturally be free and unrestrained.

Mrs. Zhang Fu did not think her husband was so frivolous. On the contrary, her husband was talented, easy-going, lively, and considerate. She couldn't be more satisfied, so she looked at her husband with love in her eyes.

The little maid Yu Yu also thinks the master is very handsome.

Da Fangfeng admired Zhang Baichuan's talent and learning. He looked down on those rotten scholars who could only make fuss, but he sincerely admired people like Zhang Xiucai who knew both astronomy and geography.

Zhang Zhixiang was still in shock. He murmured and asked: "Where is the Yin Yang fish?"

"This... you should ask the Heavenly Master. It also involves He Tu, Luo Shu, and the Five Elements. Although I can explain it to you, the connection in practice is not clear. It is better for the Heavenly Master to explain it.

.”

"Um……"

Zhang Zhixiang was a little distracted, but Zhang Baichuan didn't want to look at his nerdy look, so he pulled him over, held him in his arms, and said, "I've finished teaching you the serious knowledge. Dad will teach you something more useful."

"Come, let the rain come."

"Anping, look at the rain. If you want to praise the rain, how should you praise it?"

Zhang Zhixiang looked at the rain blankly. The little maid is ten years old this year. Although she has not grown, she is pretty and pleasant. After thinking for a while, he said: "It is very clean, like spring grass, soft and smooth, fresh and natural."

."

"Oh... Not bad, you have some talent. So if you don't know Yu Yu, how will you strike up a conversation with her?"

"ah?"

Zhang Zhixiang probably realized what his father was teaching him. Yu Yu also blushed and said in disbelief: "Master!!"

Zhang Baichuan laughed loudly: "Yu Yu, will it be good to marry Anping in the future?"

"I know how to make fun of you!"

He blushed and retorted, and Yu Yu ran away, which made Zhang Baichuan even happier. He continued to teach his son a unique skill, and Zhang Fu didn't stop him even after watching...

Zhang Zhixiang looked helpless, "We are only five years old, dad."

…

After staying at home for half a day, Zhang Zhixiang went back to the mountain. The main reason was that because of Fangfeng's size, the Zhang family had no conditions for him to stay overnight, so they couldn't let him sleep on the ground.

Before reaching the top of the mountain, I saw a little girl sitting on the bluestone steps.

Wearing a bright red coat, she looked festive and cute. She held her face with both hands, pouted her little mouth and puffed up like a little puffer fish, looking very cute and cute.

Only then did Zhang Zhixiang remember that she seemed to have told him yesterday that she wanted to go down the mountain to play together.

He forgot...

"Um... Dudu, didn't the imperial envoy deliver a lot of fruits yesterday? Let's make strawberry smoothie."

"Strawberry smoothie?"

Zhang Jingdu was confused and curious, and the ferocious look on his face could no longer be maintained. This made Zhang Zhixiang relax. The origin of strawberries was also Shangzhou. Zheng He's fleet must have had such "exotic flowers and exotic herbs" at the time.

Collected, but not many people have introduced them, but some are definitely cultivated in the royal gardens. The fruit shape of strawberries is not large, and the taste is also sour. He tried one yesterday and found it a bit hard to eat.

But if it is boiled with sugar to make strawberry jam, then it will be no problem.

There is no industrial waste gas these days, and the snow is still very clean. Take a bowl of snow, top it with strawberry jam, tsk tsk...

(ps: Strawberries are also a product of the Americas. Regardless of whether it is proved or not, just assume that the Ming Dynasty and Zheng He’s fleet in the book went to the Americas. After all, this is a fantasy novel about fictional history. In addition, there is a latitude and longitude network on the Kunyu Wanguo Complete Map.

)

(ps: "Southern Yunnan Materia Medica" was written in 1436, which contains records of the medicinal value of corn. "Ming Dynasty Records" records that the price of corn in the 5th year of Jiajing was one stone and five coins. This shows that in 1526, the price of corn in the market

The transaction volume is large enough to be worth recording.)
Chapter completed!