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As a cultured, intellectual, theoretical physicist who became a disciplined military organizer, Oppenheimer represented the shift away from the idea that scientists had their "heads in the clouds" and that knowledge of esoteric subjects like the composition of the atomic nucleus had no "real-world" applications.
A model of an atomic nucleus showing it as a compact bundle of protons (red) and neutrons (blue), the two types of nucleons.In this diagram, protons and neutrons look like little balls stuck together, but an actual nucleus (as understood by modern nuclear physics) cannot be explained like this, but only by using quantum mechanics.
The prevailing model of atomic structure before Rutherford's experiments was devised by J. J. Thomson. [1]: 123 Thomson had discovered the electron through his work on cathode rays [2] and proposed that they existed within atoms, and an electric current is electrons hopping from one atom to an adjacent one in a series.
The first two reactions that the Berlin group had observed were light elements created by the breakup of uranium nuclei; the third, the 23-minute one, was a decay into the real element 93. [103] On returning to Copenhagen, Frisch informed Bohr, who slapped his forehead and exclaimed "What idiots we have been!"
For 18th-century discoveries, around the time that Antoine Lavoisier first questioned the phlogiston theory, the recognition of a new "earth" has been regarded as being equivalent to the discovery of a new element (as was the general practice then). For some elements (e.g. Be, B, Na, Mg, Al, Si, K, Ca, Mn, Co, Ni, Zr, Mo), [51] this presents ...
Nuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or more smaller, lighter nuclei and
Hydrogen was known to be the lightest element, and its nuclei presumably the lightest nuclei. Now, because of all these considerations, Rutherford decided that a hydrogen nucleus was possibly a fundamental building block of all nuclei, and also possibly a new fundamental particle as well, since nothing was known to be lighter than that nucleus.
Sir James Chadwick (20 October 1891 – 24 July 1974) was an English physicist who received the Nobel Prize in Physics in 1935 for his discovery of the neutron.In 1941, he wrote the final draft of the MAUD Report, which inspired the U.S. government to begin serious atom bomb research efforts.