It is called "the most beautiful experiment in physics" by Einstein. Who operates it?

Author:High Energy Institute of the C Time:2022.06.27

In 1895, Lunqin discovered X -ray, but what exactly was X -ray?

A physicist believes that X -rays are electromagnetic waves. He imagined that as long as the distance between the wavelength of the X -ray and the atom (ion) in the crystal is approaching, the phenomenon of the electromagnetic wave can be observed when the crystal is illuminated by X -ray. With his encouragement, the two young people performed this experiment and succeeded in 1912: X -rays interfered through crystals and form rules on the negatives. This interpretation of the micro -laws of crystals was hailed as "the most beautiful experiment" by Einstein.

And this physicist is Marx von Lauer.

"Many people think that X -rays are a particle flow, but I still think it is an electromagnetic wave, but no one can prove it yet."

In the summer of 1909, in a conference room at the School of Physics at the University of Munich, a young physics professor Max von Lauer excitedly preached.

Several of them are his colleagues, including Lunqin's student Kniping, the teaching assistant Flidridge of the school Professor of the school, and Evar, a high school student at the University of Munich.

Everyone often meets and is familiar with each other, so speaking is more direct.

University of Munich, Germany, picture source study abroad

As one of the most prestigious comprehensive universities in Europe and the world, two well -known professors at the University of Munich in the early 20th century are very popular, one of which is Laos.

In addition to the wonderful lectures, Laos also often invited colleagues to participate in the discussion. The topic of the discussion was usually cutting -edge technology and new concepts of science at that time.

Since 1908, the theme of Lauer's discussion is the discussion of the essence of X -ray. In 1895, physicist Lunqin discovered X -rays and won the first Nobel Prize in Physics.

Since then, discussions on its essential issues have been hot, and it has become more and more trend.

This was a scene where Lauer spoke at the discussion.

New rays of peers

Laos and Eval and Kony discussed fiercely, and no one persuaded anyone.

"Can I use X -ray to illuminate the solid and judge according to the irradiation situation?" Eval suddenly made a suggestion.

"It should be used to illuminate the crystal with X -rays to see if the interference is generated. Because the internal structure and movement of general solids are too complicated, the crystal is not only simple internal structure and certain rules." Lau'er was also inspired. "If interference is generated, interference is generated Phenomenon, then X -ray is an electromagnetic wave. "

The diffraction phenomenon of the waves, the source of the picture source, the new physics network

Lae's reasonable reason. Waves have refraction, interference, diffraction, etc. If X -rays are also refracted and interfered like light, then it must be an electromagnetic wave.

The problem is that the wavelength of the X -ray is very short, and the refractive index is very small. With the technology at the time, scientists could not observe its refractive situation at all. Only by observing the interference or diffraction of X -rays can it prove whether it is an electromagnetic wave.

After all, I studied X -rays for some years, and Laos was in a word. But he understands more that to prove this, you must plan for precision experiments. Friends Einstein also told him like this.

New discovery of the most beautiful experiments

Good things are more grinding. When Lau'er was about to find Eval to experiment with his peers, he received a notice from a prestigious university in French Frankfurt University. This drag was 3 years.

In the spring of 1912, as soon as he returned to the University of Munich, he found Eval and Friedrich and began experiments to pursue the essence of X -ray.

He asked Eval to make a set of equipment, including the continuous glowing X -ray light source, photographing film, and regular square chips. The size of the square chip is only half of the negatives.

During the experiment, he first let Flidrich block the natural light, and then flattened the light source of X -rays with the photo negatives, about one meter apart, and finally placed the square chip in the middle of the light source and the negative.

They observed that they had spots with the rules of arrangement. Obviously, the spots are generated by X -rays through square chips.

The results of the X -ray crystal around Laowe,

Picture Source Physics Double Monthly Network Network

"This should be the diffraction phenomenon," Evar first, "the diffraction phenomenon shows that X -rays have the nature of electromagnetic waves."

"It makes sense. But we have to try a few more chips, at least ten, so as not to say that this is a coincidence." Laur emphasized.

Next, they replaced a variety of different substances in the experiment, and the negatives appeared on the chip. In other words, the diffraction phenomenon occurs when X -rays penetrate the chip.

The so -called diffraction means that during the spread of waves, if the wavelength is blocked, the waves can continue to spread around. Sound wave is the best example.

Soon, Lauer published a paper on X -rays. In the article, he started with the diffraction theory of light, explained the diffraction theory of X -rays in the crystal in a geometric method, and finally summarized that X -rays are an electromagnetic wave, which will have important use in the future.

He also pointed out in the text that the diffraction pattern produced by different crystals when receiving X -ray radiation can also reflect the discipline of atom distribution inside the crystal. This is the basic principle of X -ray diffraction.

Laos' experimental principle, picture source new physics network

Einstein lamented after seeing the papers of his close friends that the experiment that revealed the micro -law of the crystal was "the most beautiful experiment in physics", and Lauer also won the 1914 Nobel Prize in Physics.

The X -ray diffraction theory discovered by Lauer was later applied to the crystal structure of metal and alloy, and has obtained many new discoveries with significant significance. The discovery of X -ray diffraction has promoted the development of X -ray analysis. With the innovation of technology, it combines with computer technology to speed up the analysis speed and accuracy of crystal research.

Scientists have invented the X -ray diffraction device specifically used to study the atomic structure of the ore to shoot rocks that are used to the depth of the earth.

It can be said that it is precisely because of the X -ray diffraction theory that a accurate "chest permeability" can be taken to the earth.

On the other hand, Lauer has proved the characteristics of electromagnetic waves from theoretical to experiments that X -rays have electromagnetic waves and will occur with crystals. This theory effectively promotes the development of solid physics and is a milestone discovery in solid physics.

Scientific model compete for each other

After the crystal diffraction of X -rays was found to be a Nobel Prize, Lauer went to teach at the University of Zurich, Frankfurt University, and Humboldt University, and was well received by teachers and students.

In 1919, he returned to the University of Berlin, Germany as a professor of physics. Since then, he has been settled in Germany and has been elected as the president of the German Institute of Physics and has become one of the authorities of the German physics community.

Lauer's official photo, picture source Physical Double Monthly

Geng's upright Laue offended the Nazis and was restricted at a time. However, he tried his best to save his peers, maintain the dignity of science, and received the respect of the industry.

At the international crystallization conference hosted by the Royal Society in 1946, scientists in various countries praised him as "a respectable person" and "a model of scientists."

In 1957, the French government awarded the Medal of Honorary Corps to recognize his dignity and freedom of defending scientists.

There is also an interesting thing about Laue and the Nobel Prize in Physics.

In 1940, Germany occupied Denmark and the Nazi government sent troops to search scientists Bohr's laboratory. Boer attaches great importance to the Nobel prize medal entrusted by Lauer. With the help of chemist Hexi, he put the pure gold -made Nobel prize medal in Wangshui (hydrochloride and nitric acid mixture) to dissolve, which allowed the medal to escape.

Nine years later, the Nobel medal return ceremony was held in Chicago, and the mayor returned the recasting medal to Laos. This is also a good story in the history of the Nobel Prize.

Lauer Centennial Stamp Stamp, Physics Physics Double Monthly Network issued by Germany