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400 BCE
Democritus
Born: 460 BCE
Died: 370 BCE
Year of Discovery: 400 BCE. Naming the atom, created theories about particles.
Summary: Democritus believed the atoms were unbreakable into smaller parts, suggested all matter was formed of different properties of this particle, and determined the properties of matter.
Fact: He published over 70 books in his lifetime. -
400 BCE
Democritus Discovery
Year of Discovery: 400 BCE. Naming the atom, created theories about particles.
Summary: Democritus believed the atoms were unbreakable into smaller parts, suggested all matter was formed of different properties of this particle, and determined the properties of matter. -
John Dalton's Discovery
Year of Discovery: 1803
Summary: Studies led to a conclusion that gases had to be created out of small particles. He created a new atomic theory, saying that matter is made of small, invisible parts that are not capable of being changed or destroyed. Dalton said that each element had a different atom. -
John Dalton
Born: September 6, 1776
Died: June 27, 1844
Year of Discovery: 1803
Summary: Studies led to a conclusion that gases had to be created out of small particles. He created a new atomic theory, saying that matter is made of small, invisible parts that are not capable of being changed or destroyed. Dalton said that each element had a different atom.
Fact: In his later years, Dalton put the scientific research on hold and focused on teaching. -
JJ Thomson Discovery
Year of Discovery: 1897
Summary: Created experiments designed to study the nature of electric discharge within a high-vacuum cathode-ray tube, an area being investigated by many other scientists at the time. -
JJ Thomson
Born: December 18, 1856
Died: August 30, 1940
Year of Discovery: 1897
Summary: Created experiments designed to study the nature of electric discharge within a high-vacuum cathode-ray tube, an area being investigated by many other scientists at the time.
Fact: JJ Thomson earned a knighthood in 1908. -
Robert Andrew Milikan
Born: March 22, 1868
Died: December 19, 1953
Year of Discovery: 1909
Summary: He designed the "oil drop experiment" to measure elementary charge. Milikan also wanted to know how to quantify the change of an electron.
Fact: He was the first person to graduate with a Ph. D. in physics in Columbia. -
Robert Andrew Milikan's Discovery
Year of Discovery: 1909
Summary: He designed the "oil drop experiment" to measure elementary charge. Milikan also wanted to know how to quantify the change of an electron. -
Ernest Baron Rutherford's Discovery
Year of Discovery: 1911, discovered the nucleus
Summary: Rutherford discovered the nucleus using the gold foil experiment. -
Ernest Baron Rutherford
Born: August 30, 1871
Died: October 19, 1937
Year of Discovery: 1911, discovered the nucleus
Summary: Rutherford discovered the nucleus using the gold foil experiment.
Fact: He was the fourth of twelve children -
Niels Henrik David Bohr
Born: October 7, 1885
Died: November 18, 1962
Year of Discovery: 1913
Summary: Proposed a theory for the hydrogen atom, based off the quantum theory, where some physical quantities take only discrete values. Bohr discovered that electrons move around the nucleus, only in prescribed orbits. Also, he discovered that if electrons maneuver to a lower-energy orbit, the difference is sent out as radiation.
Fact: He was president of the Royal Danish Academy of Sciences. -
Niels Henrik David Bohr's Discovery
Year of Discovery: 1913
Summary: Proposed a theory for the hydrogen atom, based off the quantum theory, where some physical quantities take only discrete values. Bohr discovered that electrons move around the nucleus, only in prescribed orbits. Also, he discovered that if electrons maneuver to a lower-energy orbit, the difference is sent out as radiation. -
Werner Karl Heisenberg
Born: December 5, 1901
Died: February 1, 1976
Year of Discovery: 1925
Summary: Heisenberg believed that Niels Bohr's previous theory gave a good description of the spectrum made by the hydrogen atom, but this needed to be developed to suit more complicated atoms and molecules. In 1925, Werner formulated a type of quantum mechanics based on matrices.
Fact: He won a Noble Proze in Physics in 1932. -
Werner Karl Heisenberg's Discovery
Year of Discovery: 1925
Summary: Heisenberg believed that Niels Bohr's previous theory gave a good description of the spectrum made by the hydrogen atom, but this needed to be developed to suit more complicated atoms and molecules. In 1925, Werner formulated a type of quantum mechanics based on matrices. -
Erwin Rudolf Josef Alexander Schrodinger
Born: August 12, 1887
Died: January 4, 1961
Year of Discovery: 1926
Summary: Erwin is known for, his greatest discovery, the Schrodinger's Wave Equation. This equation is a result from his dissatisfaction with the quantum condition in Bohr's orbit theory and his beliefs that the atomic spectra should be determined by a certain type of eigenvalue problem.
Fact: After Erwin finished his chemistry studies, he devoted himself, for many years, to Italian painting. -
Erwin Rudolf Josef Alexander Schrodinger's Discovery
Year of Discovery: 1926
Summary: Erwin is known for, his greatest discovery, the Schrodinger's Wave Equation. This equation is a result from his dissatisfaction with the quantum condition in Bohr's orbit theory and his beliefs that the atomic spectra should be determined by a certain type of eigenvalue problem. -
Sir James Chadwick's Discovery
Year of Discovery: 1932
Summary: Chadwick made a fundamental discovery in the domain of nuclear science. With this discovery, he proved the existence of neutrons. With a new tool in atomic disintegration, need not overcome electrical barrier, allows it to be capable of penetrating and splitting the nuclei of the heaviest elements; paving the way towards fission of uranium 235 and the creation of atomic bombs. -
Sir James Chadwick
Born: October 20, 1891
Died: July 24, 1974
Year of Discovery: 1932
Summary: Chadwick made a fundamental discovery in the domain of nuclear science. With this discovery, he proved the existence of neutrons. With a new tool in atomic disintegration, need not overcome electrical barrier, allows it to be capable of penetrating and splitting the nuclei of the heaviest elements; paving the way towards fission of uranium 235 and the creation of atomic bombs.
Fact: Sir James was knighted in 1945
