More than a thousand years ago, Mozi conducted experiments on pinhole imaging. He clearly pointed out that light travels in straight lines, and the image formed by an object passing through a small hole is an inverted image. This is because when light passes through an object and then passes through the small hole, due to the straight line propagation of light, the upper part of the object is imaged below, and the lower part of the object is imaged above, so the image formed is an inverted image. He also discussed the relationship between the size of the image and the obliqueness of the object and the distance of the light source. He pointed out that if the object is oblique or the light source is far away, the shadow will be long and thin; if the object is upright or the light source is close, the shadow will be short and thick; if it is reflected light, the shadow will be formed on the object. between the light source.
In addition, Mozi also conducted quite systematic research on plane mirrors, concave mirrors, convex mirrors, etc., and derived a series of basic principles of geometric optics. He pointed out that the plane mirror formed an image of the same size and symmetry in distance, but the left and right images were reversed. If two or more plane mirrors are facing each other, repeated reflections will occur, forming countless images. The image of a concave mirror forms an erect image within the "middle". The image that is far from the "middle" is large, and the image that is close to the "middle" is small. At the "middle", the image is as big as the object; in the "middle" Outside, an inverted image is formed, with the near "middle" image being large and the far "middle" image being small. A convex mirror only forms an erect image, with a large near image and a small far image.
The "center" here is the center of the spherical mirror. Although Mozi was not able to distinguish the difference between the center of the sphere and the focus, and confused the center and the focus together, his conclusion is basically consistent with the imaging principle of modern spherical mirrors.
In the history of optics, Mozi was the first scientist to conduct systematic research on geometric optics. It would not be an exaggeration to say that Mozi laid the foundation of geometric optics, at least in China. As Joseph Needham said in the Physics Volume of "History of Chinese Science and Technology", Mozi's research on optics was "earlier than what we know about Greece" and "India cannot compare with it."
At this moment, when Mo Huai heard Li Zexuan's answer, he was not as surprised as the previous two times, but continued to ask: "Why is there an image of an inverted object~? If Mr. Li doesn't want to explain, he can think of this question as my question The fourth question~!”
Li Zexuan waved his hand and said with a smile: "No, no, since the big guy wants to hear why, then the kid will explain it properly. It doesn't count as one of the five questions~!"
He is now more and more interested in wooing Mo Huai, so his self-proclaimed title has changed from the lord at the beginning to the boy. Although he is confident of winning this bet, he still wants to give others a little face and let others lose. I am convinced, so that Mo Huai will be willing to teach students in the future and do his best~! This is not called cowardice, but the demeanor of a winner~!
Li Gang frowned slightly, secretly thinking that Li Zexuan was a bit too much, but Mo Huai was also an old friend of his, so he couldn't just jump out and stop him at this time, right?
Li Zexuan asked Xiao Anren to bring pen and ink, and then motioned to Mo Huai to come over. He drew the light path diagram of the small hole imaging system and said slowly:
"Look, giant! This is a candle. The flame of the candle is seen to be composed of many small luminous points. Each luminous point emits light in all directions. There will always be a small beam of light passing straight through the small hole. A small light spot is formed behind the small hole. Therefore, each luminous point on the candle flame will form a corresponding light spot on the white paper, and all the light spots on the white paper will form an image of the candle flame..."
Following Li Zexuan's narration, Mo Huai suddenly realized that now he finally knew what was happening and why. But at the same time, he looked at Li Zexuan with a very strange look, as if he was looking at a monster~!
At this moment, Mo Huai became very curious about Li Zexuan's origins. First of all, being able to become a martial arts master at the age of fourteen or fifteen years old was already a unique exception in the world. However, Li Zexuan was in these very special sects. In his field, he actually has such profound attainments, both in civil and martial arts, and in every aspect he can reach an existence that is beyond the reach of ordinary people. Mo Huai can't imagine what kind of family and what kind of master can teach such a monster~?
"How is it~? I wonder if what I said is right~?"
Li Zexuan's scalp felt numb due to Mo Huai's eyes, so he couldn't help but say.
Mo Huai nodded silently without saying a word.
Li Zexuan said: "Then please ask the master to continue with the fourth question~!"
Hearing this, Mo Huai looked away from Li Zexuan, sighed deeply, then bent down to Li Zexuan, cupped his hands and said: "There's no need to go out, I admit defeat~! From now on, I will let this old man do whatever he wants. Driven by a man from Li County, he works hard without asking for reward~!"
"Uncle~! No~!"
"Uncle~! Don't do it~!"
Mo Zhong and Mo Yun were shocked when they saw this, and they yelled.
As a giant of the Mohist family, Mo Huai's knowledge and martial arts are the role models they, the Mohists who adhere to Mohism, have admired and pursued since childhood. Now, the man who is like a god in their eyes has actually bowed his head to a young man of fourteen or fifteen years old. How can they endure this~? Although Li Zexuan is indeed very powerful, Mo Zhong and Mo Yun still cannot accept this reality.
"Shut up~! As a giant of the Mohist family, how can I not keep my word~? Mo Zhong, Mo Yun, you two should step aside for now. In the future, I will choose the next giant of the Mohist family~!"
Hearing this, Mo Huai reprimanded loudly, and then he cupped his hands to Li Zexuan and said: "Master Li, please give me one month's grace. After I return to the Mo family's residence and select the next tycoon, I will return to Chang'an wholeheartedly. Teach students~!”
Now with Mo Huai's gentle request, where is the high-spiritedness from the beginning~? It’s a bit more desolate at the end of the hero~!
Li Gang looked at it and felt extremely unbearable. After all, the person in front of him was an old friend he had known for many years, so he said: "Brother Mo, there is no need to be like this~! Your status as a giant is not the same as your status as a teacher at Yanhuang Academy. No conflict~! Xiaoxuan is not that kind of unkind person, he will not restrict your freedom~! You can manage the affairs of the Mohist family while teaching at Yanhuang Academy~! Besides, the Mohist family has declined to this day, How many more affairs do you need to manage~?"
The corner of Li Zexuan's mouth curled up, secretly thinking that his opportunity had come. He quickly interjected: "Mr. Li is right, if you go to Yanhuang Academy to teach, I will never restrict your freedom, and you will have the salary you deserve. I will never shortchange you by a penny~! In addition, Big Brother, you can move the Mo family's headquarters to Chang'an~!
At that time, the boy will be responsible for settling all the Mohists in the Mo family. If there are Mohists among them who are as proficient in mechanics, optics or mechanical equipment as you are, I am also willing to hire them to Yanhuang Academy~! As for the salary and salary of college teachers, you must also know it, so I won’t repeat it. What do you think~? "
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