Chapter 71 Rutherford’s wonderful speech
At the European Radiology Conference at the University of Paris, Rutherford began to give an impassioned speech about his results.
“After Professor Becquerel discovered radioactivity in 1896, the Curies extracted natural radioactive elements from asphalt: polonium (read Poe) and radium.”
“Their experiments The results confirmed that there is indeed such a strange element in nature that can emit matter spontaneously."
"My mentor, Professor Thomson, was also interested in radioactivity, so he asked me to study at Bekele. On the basis of Professor Er, he studied the radioactivity of uranium salts."
"I have two research goals. First, what are the natural rays emitted by radioactive elements; second, what is the radioactive mechanism of elements."
"For the first goal, I designed the following Experiment." As he spoke, Rutherford began to draw a schematic diagram on the blackboard.
“I used materials of different thicknesses to wrap uranium salts, and then observed the natural rays on the photosensitive film.”
“I was surprised to find that there are two natural rays of uranium salts. "
"The first type can be easily blocked with a single layer of aluminum foil or even paper. I named it alpha rays."
"The second type requires many layers of aluminum foil to block it. I named it beta rays."
"Based on these two rays, I thought of the French physicist Willard last year. It was discovered that barium chloride containing radium would also emit a kind of ray."
"So, through various tests, I finally found this kind of ray in uranium salt, and I put it in. Named gamma rays.”
“According to experimental results, gamma rays are much more penetrating than beta rays and alpha rays.”
At this point, everyone was impressed by Luther. I was impressed by Fu's ingenious experiments, but also shocked by his meticulousness.
Li Qiwei expressed deep emotion that the development of physics sometimes relies on the sudden flash of inspiration and information sharing of geniuses.
At this time in China, most people were very self-conscious, fearing that the disciples would starve to death. He shook his head slightly.
Rutherford saw everyone's expressions of excitement and became more confident.
“Next, I want to study the nature of these three rays.”
“So, I used the deflection principle of the magnetic field to add a magnetic field to the path of the rays.”< br>
"It turns out that the deflection directions of alpha rays and beta rays are opposite. Based on reasoning, I proved that alpha rays are positively charged and beta rays are negatively charged."
"While gamma rays continue to propagate in a straight line, So it is uncharged. "
"Due to the nature of beta rays, Professor Becquerel and Marie Curie have done a lot of research and calculated its charge-to-mass ratio, confirming that it is an electron flow. "
“And I have once again proved this statement through experiments.”
“So, I further studied alpha rays in a targeted manner.”
"My mentor, Professor Thomson, has proven that electrons will be generated when electricity is passed through a glass tube close to a vacuum, so I introduced alpha rays into the glass tube for observation."
"It turned out that after the alpha rays are combined with electrons, , Helium atoms actually appeared in the glass tube."
"This shows that there are positively charged helium ions that capture electrons to form helium atoms."
"So, I am sure. The alpha rays emitted by the uranium salt are positively charged helium ions. "
"Of course, I did some additional experiments later to measure the charge of the alpha rays, which is consistent with the inference."
< br>
"This phenomenon proves that the so-called radioactivity is the transformation of one element into another element."
"Because after the uranium element emits helium ions, its own composition will inevitably change and become a new element. element."
"As for the time it takes for this element to transform, I invented the term radioactive half-life to describe it."
"This is the result of my paper published in the journal Nature. . ”
“So, my next step is to study the nature of gamma rays; the second is to figure out what is the structure inside the atom and why it can emit three kinds of rays. .”
"As for the interior of atoms, I can share my latest experimental results with you in advance."
"I have recently been trying to use alpha rays to bombard atoms of different elements to see how the alpha rays will be affected by the collision. What impact."
"However, because this experiment requires very sophisticated instruments, my results are still relatively few." "However, I think this method of studying the internal structure of atoms can be of reference to everyone. ”
“I will publish the relevant results in Nature in the near future. I welcome your corrections at that time. ”
"My speech is over. Everyone is welcome to ask questions and discuss together."
As soon as Rutherford finished speaking, everyone present stood up and applauded. His research was so exciting and inspiring.
If Maxwell unified electromagnetism, then Rutherford unified radioactivity.
He not only explained the nature of radioactivity, but also went deep into the study of the inside of atoms. Everyone couldn't help but worship him.
Moreover, Rutherford also incorporated the previous research results into his own theoretical framework to form a systematic science.
From now on, the study of radioactivity will have a theoretical basis and will no longer be an experiment relying solely on luck.
Therefore, more and more physicists are joining radioactive research.
There are too many unsolved mysteries in this field, and figuring out one of them is a major achievement and is world-famous in the physics world.
Li Qiwei lamented that he has changed history more and more.
In real history, in 1911, Rutherford first bombarded gold foil with alpha rays and discovered that the positive charges in the atoms were not evenly distributed inside, but concentrated on a small core.
He called this core the "nucleus."
Then in 1919, he bombarded the nitrogen nucleus with alpha rays and produced a particle from the nitrogen nucleus.
Measurements found that the charge and mass of this particle were both in a standard unit, so it was named "proton".
Now, Rutherford began to use alpha rays to explore the internal structure of atoms a full decade ahead of schedule, which undoubtedly greatly accelerated the development of atomic theory.
Once he achieves a breakthrough in his research on atomic structure, Rutherford's reputation will definitely skyrocket and he will become a top physicist.
Xu Qitai, who was next to Li Qiwei, was already stunned.
He was shouting crazily in his heart, is this the most cutting-edge physical experimental research in the world? It was simply too amazing to describe.
In comparison, the experiments I did in China before were just like children's playing house.
At this moment, Xu Qitai's fighting spirit rose in his heart. He would also become an experimental physicist like Rutherford in the future.
Soon, people began to ask questions in the venue.
First there were the big guys like Becquerel and the Curies, and then there were the French radiology giants like Poincaré and Willard whom Ridgway met for the first time.
Rutherford talks and laughs, explaining his work with ease and humor.
Then there were questions from ordinary professors and students.
Because the study of radioactivity does not involve advanced mathematical knowledge, many students prefer to choose this direction.
Suddenly, Anders stood up and asked pretending to be innocent: "Dear Bruce Lee, I just saw you shaking your head slightly at Professor Rutherford's speech."
"Excuse me, do you think experimental physics is not as important as theoretical physics?"
Everyone in the venue was startled, and then felt a little embarrassed.
And Ridgway smiled.
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(End of this chapter)