nauka: Discovery of the neutron

Evidence: 100 • authority: 72

The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics in the first half of the 20th century. Early in the century, Ernest Rutherford used alpha particle scattering to discover that an atom has its mass and electric charge concentrated in a tiny nucleus. By 1920, isotopes of chemical elements had been discovered, the atomic masses had been determined to be approximately integer multiples of the mass of the hydrogen atom, and the atomic number had been identified as the charge on the nucleus. Throughout the 1920s, the nucleus was viewed as composed of combinations of protons and electrons, the two elementary particles known at the time…

Evidence: 45 • authority: 72

A neutron is a subatomic particle, symbol n or n0, that has no electric charge, and a mass slightly greater than that of a proton. The neutron was discovered by James Chadwick in 1932, leading to the discovery of nuclear fission in 1938, the first self-sustaining nuclear reactor (Chicago Pile-1, 1942), and the first nuclear weapon (Trinity, 1945). Neutrons are found, together with a similar number of protons, in the nuclei of atoms. Atoms of a chemical element that differ only in neutron number are called isotopes. Free neutrons are produced copiously in nuclear fission and fusion. They are a primary contributor to the nucleosynthesis of chemical elements within stars through fission, fusio…

Evidence: 41 • authority: 72

English inventions and discoveries are objects, processes or techniques invented, innovated or discovered, partially or entirely, in England by a person from England. Often, things discovered for the first time are also called inventions and in many cases, there is no clear line between the two. Nonetheless, science and technology in England continued to develop rapidly in absolute terms. The trend continues. According to a Japanese research firm, the UK generated over 40% of the world's inventions and discoveries that in the past 50 years became internationally recognized and/or applied, followed by France with 24% and the US with 20%. England was a leading centre of the Scientific Revolut…