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Democritus
Democritus:
370 BC- 465 BC
Democritus was born in Abdera, Greece in 460 BC. He lived to be 90 years old, dying in the year 370 BC. Democritus was never married. His mentor, Leucippus, originally came up with the atomic theory, but it was then adopted by Democritus. The atomic theory stated that “The universe is composed of two elements: the atoms and the void in which they exist and move.” According to Democritus atoms were miniscule quantities of matter. Democritus hypothesized that atoms canno -
Antoine Lavoisier
Antoine Lavoisier
1743-1794
Was a French chemist who revolutionized chemistry and was called the “father of modern chemistry.”
Lavoisier found that mass is conserved in a chemical reaction. The total mass of the products of a chemical reaction is always the same as the total mass of the starting materials consumed in the reaction. This is called the Law of Conservation of Matter.
He named the elements carbon, hydrogen, and oxygen. He discovered oxygen's role in combustion and respiration. He est -
John Dalton
John Dalton
1776-1844
Was an English Chemist, physicist and meteorologist who was credited with pioneering modern atomic theory = that every form of matter (solid, liquid, or gas) was made up of small individual particles, or atoms. He was the first scientist to explain the behavior of atoms in terms of the measurement of weight.
Dalton's Law = the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space. -
Dmitri Mendeleev
Dmitri Mendeleev:
1834-1907
Dmitri Mendeleev was a Russian chemist and inventor. He formulated the Periodic Law, created his own version of the periodic table of elements, and used it to correct the properties of some already discovered elements and also to predict the properties of eight elements yet to be discovered. Mendeleev was born on 8 February 1834 and died on 2 February 1907 at age 72. -
Eugen Goldstein
Eugen Goldstein:
1850-1930
Eugen Goldstein was a German physicist. He was an early investigator of discharge tubes, the discoverer of anode rays, and is sometimes credited with the discovery of the proton. In the 1870s Goldstein undertook his own investigations of discharge tubes, and named the light emissions studied by others Kathoden Strahlen, or cathode rays. He discovered several important properties of cathode rays, which contributed to their later identification as the first subatomic par -
JJ Thomson
JJ thomson
1856-1940
Was an English physicist whose research in the cathode rays led to the discovery of the electron. He studied positively charged ions and discovered that neon was composed of two different kinds of atoms, and proved the existence of isotopes in a stable element. -
Max Planck
Max Planck:
1858-1947
Max Planck was a German theoretical physicist who originated quantum theory, which won him the Nobel Prize in Physics in 1918. Planck made many contributions to theoretical physics, but his fame as a physicist rests primarily on his role as an originator of the quantum theory. However, his name is also known on a broader academic basis, through the renaming in 1948 of the German scientific institution, the Kaiser Wilhelm Society (of which he was twice president), as the Ma -
Robert Milikan
Robert Millikan
1868-1953
Was an American experimental physicist who was honored with eh Nobel Prize for Physics in 1923 for his measurement of the elementary electric charge and for his work on the photoelectric effect.
Proved that radiation can be extraterrestrial in origin and named it “cosmic rays” -
Ernest Rutherford
Ernest Rutherford:
1871-1931
was a New Zealand-born British physicist who became known as the father of nuclear physics.Rutherford moved in 1907 to the Victoria University of Manchester (today University of Manchester) in the UK, where he and Thomas Royds proved that alpha radiation is helium nuclei. Rutherford became Director of the Cavendish Laboratory at the University of Cambridge in 1919. Under his leadership the neutron was discovered by James Chadwick in 1932 and in the same year the fir -
Niels Bohr
Niels Bohr:
1885-1962
The discoveries of the electron and radioactivity at the end of the 19th century led to different models for the structure of the atom. In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr's theory could explain why -
Henry Moseley
Henry Moseley:
1887-1915
Henry Moseley was born in Weymouth, Dorset, on the south coast of England in 1887. His father Henry Nottidge Moseley(1844–91), who died when Henry Moseley was quite young, was a biologist and also a professor of anatomy and physiology at the University of Oxford. Before Moseley's discovery, the atomic numbers (or elemental number) of an element had been thought of as a semi-arbitrary sequential number, based on the sequence of atomic masses, but modified somewhat where c -
Erwin Schrodliger
Erwin Schrodinger:
1887-1961
Erwin Schrodinger was a Nobel Prize-winning Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave mechanics: he formulated the wave equation (stationary and time-dependent Schrödinger equation) and revealed the identity of his development of the formalism and matrix mechanics. Schrodinger was born on 12 August 1887 and died on 4 January 1961 at age 73. -
James Chadwick
James chadwick
1891-1974
Was an english physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
In 1941, he wrote the final draft of the Maud report which inspired the US government to begin serious Atomic Bomb research efforts. -
Werner Heisenberg
Werner Heisenberg:
1901-1976
Werner Heisenberg was a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his work in 1925 in a breakthrough paper. In 1927 he published his uncertainty principle, upon which he built his philosophy and for which he is best known. Heisenberg was awarded the Nobel Prize in Physics for 1932. He also made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism,cosmic ra -
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