Training the Heavens

Chapter 267 Blackbody Radiation Experiment
Before coming to France, Zhang Xingjiu had already thought about his main direction. It was impossible for him to engage in invention research. With China's current industrial capabilities, no matter what he researched, the only ones who would benefit would be the developed countries in Europe and the United States.

If the gap between China and developed countries in Europe and America widens because of his own fault, Zhang Xingjiu will be doomed to death.

For example, he has the technology to synthesize ammonia in his mind. If he dares to use it, the war capabilities of European and American countries will suddenly increase. Once they have fought enough, it is easy to imagine what they will do next, so this thing must not be used.

Theoretical physics is much better. The development of theory will definitely promote the development of applications, but this often takes time, and sometimes it takes a very long time. It only requires seizing the opportunity and being slightly ahead of theoretical physicists in Europe and the United States for a few years, which will not cause too much interference to history.

The biggest problems in the field of theoretical physics now are these two dark clouds. It is very appropriate to use this to make a name for himself, because even without Zhang Xingjiu, European and American physicists will make a breakthrough soon. He just brought the time forward a little bit.

"I read in a journal that a researcher at the Imperial Physical-Technical Institute in Germany, Wien, recently derived a semi-empirical formula for blackbody radiation from a thermodynamic perspective. This formula is called the 'Wien approximation.' It hasn't been experimentally verified yet. We can design an experimental plan to test this formula."

Any object has the property of continuously radiating, absorbing and reflecting electromagnetic waves. The radiated electromagnetic waves are different in different bands, that is, they have a certain spectral distribution.

This spectral distribution is related to the properties of the object itself and its temperature, and is therefore called thermal radiation. In order to study the laws of thermal radiation that are independent of the specific physical properties of the substance, physicists have defined an ideal object - the black body, as a standard object for thermal radiation research.

In real life, coal is the substance closest to a "black body". When heated, it first emits red light (longer wavelength, lower frequency). As the temperature rises, the color of the light changes from red to yellow, and finally to blue (shorter wavelength, higher frequency).

Later, in a broad sense, any phenomenon of heated matter emitting electromagnetic waves can be called "blackbody radiation". Physicists explore the relationship between the energy, temperature and wavelength of "blackbody radiation". The formula that Wien came up with not long ago tried to use mathematical methods to describe this relationship.

It’s just that his formula is not accurate, and loopholes in the formula can be found through experiments. German physicists proved this a few months later. Zhang Xingjiu is just slightly advancing this time.

"How do you plan to do the experiment?" Pierre asked with interest. He has been in charge of the laboratory for more than ten years and is much more interested in experiments than boring theories.

"Try to heat the black body and measure data indicators at different wavelengths. Wien believed that when the wavelength tends to infinity, the energy density is independent of temperature. We can use data to test this conjecture." Zhang Xingjiu took out the experimental plan of German physicists Lummel and Prinsheim.

Lang Zhiwan pondered silently for a moment, then suddenly opened his eyes. "Theoretically, this method should work, but the measurement range needs to be larger. Wien must have conducted experiments, and the data must conform to his formula, otherwise he wouldn't have produced it."

"To conduct this experiment, we need heating equipment, a suitable blackbody, and most importantly, the thermal radiation meter invented by American scholar Langley. It's a superb measuring tool. Combined with a Rowland concave grating, it can produce a very accurate thermal radiation energy distribution curve." Zhang Xingjiu looked at Pierre. "The school lab has these devices, but ordinary students are not allowed to use them. You must come up with a comprehensive experimental plan to convince Professor Lippmann. I can help persuade him, but success is not guaranteed. Professor Lippmann is very stubborn in his academic work. If your plan is not good enough, he will not approve it," Pierre said.

"Could you give me a few approved experimental plans so I can learn how they are written?" Zhang Xingjiu was not in a hurry to start writing the plan immediately. The format of today's plans must be very different from that of later generations. If the difference is too big, Professor Lippmann might not be used to it and would reject it without even reading the content.

"No problem, I'll give it to you after class tomorrow." These are all small matters. Pierre himself is the head of the laboratory, and he has many similar plans.

"I am also very interested in this topic. Please be sure to include me when you write the proposal." Lang Zhiwan quickly interrupted. He didn't want to steal Zhang Xingjiu's idea, but he was really interested in this issue.

Zhang Xingjiu was also happy to have someone to help him, and he had a good impression of Lang Zhiwan, who would later become a member of the French Communist Party and had repeatedly expressed support for China in public. He was a genuine international friend, and he still hoped to have a good relationship with such a person.

So from that day on, Lang Zhiwan would run to Zhang Xingjiu as soon as he got out of class every day to write the experimental plan with him. Fortunately, the École Normale Supérieure in Paris and the Sorbonne University were not far away, so it was not too troublesome.

At this time, Zhang Xingjiu's guest room came in handy. Sometimes when the two of them were busy too late, Lang Zhiwan would go directly to the guest room to rest without having to run back and forth.

A week later, Zhang Xingjiu handed the written plan to Pierre. Pierre checked it first and pointed out a few minor problems in writing habits. After Zhang Xingjiu finished revising it, he gave it directly to Lippmann.

Zhang Xingjiu performed well in class. He listened carefully, answered the teacher's questions actively, and completed his homework quickly and well. He would hang out in the library whenever he had time, and Lippmann often met him when he went to look up information.

What teacher wouldn't like a student like this? So Lippmann had a very good impression of Zhang Xingjiu, and now that he saw that his experimental plan was well written, he gave him this opportunity without hesitation.

Pierre prepared the experimental equipment and venue for them, and Lang Zhiwan also slipped into the laboratory. The two began to prepare for the experiment under Pierre's guidance.

Zhang Xingjiu quickly mastered the operation of the thermal radiometer and the Rowland concave grating, and mastered the steps for heating the blackbody with great precision. Pierre was very impressed. "My lab needs an assistant with precise operation like you. When Mary and I start a new project, will you come and help us?"

Oh my god, this new project of yours isn't about pitchblende, is it? I wouldn't dare do that!
(End of this chapter)