Fermi was awarded the Planck Medal in Germany, the Lewis Scholarship of the American Philosophical Society and the Fermi Award in the United States. 1953 was elected president of american physical society. He was also awarded honorary doctor by Heisenberg University in Germany, Utrecht University in the Netherlands, Washington University, Columbia University, Yale University, Harvard University, Rochester University and Lakford University.
Fermi became an important figure for the following reasons. First, he is one of the undisputed greatest scientists in the 20th century, and he is one of the few people who have both outstanding theorists and outstanding experimenters. During his career, he wrote more than 250 scientific papers. Secondly, Fermi was a very important figure in the invention of atomic explosion, although others also played an equally important role in promoting the development of this cause.
Atomic weapons have never been used in war since 1945. For peaceful purposes, a large number of nuclear reactors are built to generate energy. In the future, reactors will become more important energy sources. In addition, some reactors are used to produce useful radioisotopes for medical and scientific research. Reactors are also a source of plutonium, a material used to make nuclear weapons. People are afraid that nuclear reactors may do harm to human beings, but no one complains that this is a meaningless invention. For better or worse, Fermi's work will have a great influence on the future world.
In order to commemorate Fermi's contribution to nuclear physics, the U.S. Atomic Energy Commission established the Fermi Prize to commend scientists from various countries who have contributed to the peaceful use of nuclear energy.
The100th chemical element americium and the Fermi unit (length unit) used in nuclear physics are all named after Fermi.
Nobel Prize
In the early 1930s, after neutron was discovered, scientists used it to bombard various elements and study nuclear reactions. A group of young people led by Fermi, an academician of the Royal Italian Academy of Sciences, have done their best. They bombarded the known elements from beginning to end in the order of the periodic table to see what would happen.
In 1934, it was thought that the last element in the periodic table was uranium 92. But when the neutron bombardment, they found that uranium was strongly activated, producing many elements. They believe that one of these uranium decay products is a new element with atomic number 93. This is because neutrons hit the uranium nucleus, increasing the atomic weight of uranium and transforming it into new elements.
After Fermi et al.' s experimental report on the new element 93 was published, newspapers all over the world immediately made a sensational report. The problem of element 93 has caused a fierce and lasting debate among scientists all over the world. Many people are sure, and many people doubt it. The reason why the debate has been delayed is the lack of an effective means to accurately separate and analyze the products of neutron bombardment of uranium.
In June 65438 +0934+10, Fermi's research team did not solve this mystery, but unexpectedly made another important discovery: the neutron collided with the hydrogen nucleus in the hydrogen-containing substance before reaching the irradiated substance, and the speed was greatly reduced; This "slow neutron" with reduced speed is more likely to cause nuclear reaction of irradiated materials. Just as a basketball that is too fast is easy to pop out of the box and a basketball that is too slow is easy to get into the basket, bombarding the nucleus with slow neutrons is quickly adopted by scientists all over the world.
1938165438+1October 10, that is, more than four years after the discovery of "Element 93", Fermi received a phone call from Stockholm, and the Swedish Academy of Science announced that Fermi had won the Nobel Prize in Physics: "This prize was awarded to Professor Enrico Fermi of Rome University in recognition of his work on neutrons. Fermi took his family to Stockholm to receive the prize. Instead of returning to Italy, he boarded a ship to America.
In this year, two chemists, Hahn and Strassman, from the Royal Institute of Chemistry in Wilhelm, Germany, cooperated with female physicist metternich to conduct experiments by bombarding uranium with slow neutrons, and separated and tested the products of nuclear reaction by chemical methods, and obtained incredible results: the uranium nucleus was split into roughly equal halves under the bombardment of neutrons, which were not new element 93, but element 56 barium! This change in the nucleus has never been found before.
1938165438+122 October, that is,12 days after the Nobel Prize was awarded, Hahn sent the report on splitting atoms to the journal Nature Science in Berlin, which published it in1939 65438+. Obviously, the Nobel Prize is wrong!
Upon hearing this amazing news, Fermi's first reaction was to come to the laboratory of Columbia University and repeat Hahn's experiment with better equipment there. The result is the same as Hahn's experiment. This fact undoubtedly embarrassed Fermi. However, contrary to people's imagination, Fermi frankly reviewed and summarized his wrong judgment, showing the noble quality of a scientist obeying the truth.
At this moment, Fermi is not thinking about personal reputation. He keeps forging ahead on the basis of others' achievements. On the basis of fission theory, Fermi quickly put forward a hypothesis: when uranium fission, neutrons will be released. These neutrons will hit other uranium nuclei and have a series of reactions until all the atoms split. This is the famous chain reaction theory. According to this theory, when fission continues, huge energy will erupt. If it is made into a bomb, its theoretical explosive power is 20 million times that of TNT!