August 30, 1871, Brightwater (New Zealand) - October 19, 1937, Cambridge (United Kingdom).
After graduating from Christchurch, New Zealand, in 1893, he moved to Cambridge University two years later to work as an assistant to Joseph J. Thomson (discoverer of the electron).
In 1898 he was appointed professor at McGill University in Montreal, Canada.
Ernest Rutherford is considered one of the fathers of this discipline for his work in atomic physics. He also researched the detection of electromagnetic radiation and the ionisation of air produced by X-rays. He studied the radioactive emissions discovered by Antoine Henry Becquerel and succeeded in classifying them into alpha, beta, and gamma rays.
In 1902, in collaboration with Frederick Soddy, Rutherford formulated the theory of natural radioactivity associated with the spontaneous transformations of the elements and collaborated with Hans Geiger in the development of the radiation counter known as the Geiger counter, and demonstrated (1908) that alpha particles are helium ions (more precisely, nuclei of the helium atom) and, in 1911, he described a new atomic model (Rutherford's atomic model), which would later be perfected by Niels Bohr.
According to this model, the atom had a central nucleus in which almost all the mass was concentrated, positive electric charges, and an electron shell (negative electric charge). In addition, he was able to experimentally demonstrate the theory mentioned above based on the deviations in the trajectory of particles emitted by radioactive substances when atoms were bombarded with them.
In 1908, he was awarded the Nobel Prize in Chemistry for discovering the disintegration of elements.
When he returned to the UK in 1907, he became a lecturer at the University of Manchester, and in 1919, he succeeded Thomson as director of the Cavendish Laboratory at Cambridge University.
In 1918, Rutherford discovered the proton while experimenting with nitrogen gas. He noticed that his instruments detected the presence of hydrogen nuclei when firing alpha particles at the gas. He concluded that these nuclei must be fundamental particles of matter, not realizing at the time that the nucleus of a hydrogen atom contains a single particle: a proton. Thus, hydrogen was assigned the atomic number 1.
However, there are known prior scientific experiments that led to this discovery. For example, the German physicist Eugene Goldstein found positive ions within the atom in 1886 through experiments with cathode rays. Joseph J. Thomson had already discovered electrons and their negative charge, indicating that there must be some other type of particle with an opposite charge in the atom.
Rutherford's experiments also established an order of magnitude for the real dimensions of the atomic nucleus.
As a curiosity, during the First World War, he studied the detection of submarines using sound waves, making him one of the forerunners of sonar.
