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400 BCE
Democritus
- Democritus was born c.460 and died in c.370 BC.
- He theorized that, "all material bodies are made up of indivisible small 'atoms'." Democritus said that atoms are so small that they cannot be broken down into smaller pieces.
- A lunar crater named after Democritus in the 20th century.
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Sir John Dalton
- Dalton was born September 5, 1766 and died July 27, 1844.
- John Dalton created what is now called Dalton's law. Dalton's law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual component gases. This means that only similar atoms in mixtures of gases repel each other and atoms that are not similar will react indifferently toward one another.
- John Dalton was a quaker.
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Joseph John Thomson
- J.J. Thomson was born December 18, 1856 and died August 30, 1940.
- Thomson concluded that, "all matter, whatever its source, contains particles of the same kind that are much less massive than the atoms of which they form a part." These are now known as electrons, which originally Thomson called corpuscles.
- Thomson received the Nobel Prize for Physics in 1906 and was knighted in 1908.
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Ernest, Baron Rutherford of Nelson
- Rutherford was born August 30, 1871 and died October 19, 1937
- Rutherford discovered that the atom is mostly made up of empty space. Nearly all of an atom's mass is concentrated in the very center. The center is positively charged, and is surrounded by negatively charged electrons.
- Earnest was the fourth child and second son of 12 children.
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Niels Henrik David Bohr
- Niels was born October 7, 1885 and died Novenber 18, 1962.
- Bohr's model of the atom included electrons in specific stable orbits. This was the first model to incorporate quantum theory.
- Bohr was notortious for setting off explosions in his university's lab.
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Robert Andrews Millikan
- Millikan was born March 22, 1868 and died December 19, 1953
- Robert Millikan accurately determined the charge that electrons carry by using the "falling-drop method". He also proved that the quantity was the same for all electrons.
- Tennis and golf were some of Millikan's favorite recreations.
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Werner Karl Heisenberg
- Heisenberg was born December 5, 1901 and died February 1, 1976.
- Werner Heisenberg developed quantum mechanics in terms of matrices. He also discovered the uncertainty principle which says that a particle's position and momentum cannot both be known as an exact measurement.
- Werner and his wife Elisabeth Schumacher had seven children.
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Erwin Rudolf Josef Alexander Schrödinger
- Schrödinger was born August 12, 1887 and died January 4, 1961.
- Schrödinger formed a theory saying the behavior of electrons in atoms can be explained by handling them mathematically as matter waves.
- For years, Schrödinger devoted himself to Italian painting.
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Sir James Chadwick
- Chadwick was born October 20, 1891, and dies July 24, 1974.
- James Chadwick and Ernest Rutherford together discovered the proton in 1919. People soon began to wonder if there are more to the series. This caused them to theorize that there were additional particles in the nucleus.
- Chadwick was imprisoned in a camp for civilians at Ruhleben during WWI.
