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Period: Jan 1, 1400 to
Science
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Jan 1, 1500
Democritus
Born: c. 460 BC Died: c. 370 BC
Studies: The soul, Perception, Theology, ethics -
Jan 1, 1500
Law of Conservation of mass
states that the mass of an isolated system will remain constant over time. -
Antoine Lavoisier
Born: 26-Aug-1743 Died: 8-May-1794
Studies: Father of modern chemistry -
John Dalton
Born: 6-Sep-1766 Died: 27-Jul-1844
Studies: in 1787 he began to keep a meteorological diary in which he entered more than 200,000 observations. -
Dalton's Atomic Theory
All matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two or more different kinds of atoms. A chemical reaction is a rearrangement of atoms. -
Dmitri Mendeleev
Born: 8-Feb-1834 Died: 2-Feb-1907
Studies: guessed the existence of three new elements so far unknown, and assigned them properties. -
J. J. Thomson
Born: 18-Dec-1856 Died: 30-Aug-1940
Studies: thought that cathode rays produced in Crookes tubes must be made of what he called "corpuscles", a single type of negatively charged particle. -
Robert A. Millikan
Born: 22-Mar-1868 Died: 19-Dec-1953
Studies: During World War I he served on the National Research Council (NRC), conducting emergency research into submarine detection. -
Ernest Rutherford
Born: 30-Aug-1871 Died: 19-Oct-1937
Studies: He made up the terms alpha ray, beta ray, gamma ray, and half-life for radioactive decay, and he was widely credited in his time as the first scientist to split the atom. -
Niels Bohr
Born: 7-Oct-1885 Died: 18-Nov-1962
Studies: stated that electrons travel in fixed orbits around the atom's nucleus, and further explained how electrons emit or absorb energy -
Erwin Schrödinger
Born: 12-Aug-1887 Died: 4-Jan-1961
Studies: Schrödinger's wave, the mathematical equation of wave mechanics that is still the most widely used piece of mathematics in modern quantum theory. -
Henry Moseley
Born: 23-Nov-1887 Died: 10-Aug-1915 Studies: he discovered Moseley's Law, which correlated wavelength and atomic number, thus demonstrating the importance of atomic number over atomic weight, as was the common belief. -
James Chadwick
Born: 20-Oct-1891 Died: 24-Jul-1974
Studies: proved the existence of neutrons, the elementary particle without any electrical charge and a fundamental building block of the atom's nucleus. -
Cathode Ray Tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. -
Plum Pudding Model
In this model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges -
Gold Foil Expermient
alpha particles not always behaving in accordance to the plum pudding model of an atom when fired at a piece of gold foil. -
Rutherford model
contained the new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume also containing the bulk of the atomic mass of the atom. -
The Bohr Model
In the Bohr Model the neutrons and protons occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun
