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John Dalton
Dalton came up with three laws: Law of Multiple Proportions, which states that if 2 elements become a compound, the ratios of the 2nd element which combine with fixed mass of the 1st element will be small ratios of small #s, Law of Definite Composition states: a compound always contains two or more dlements combined in a definite proportion of mass. The law of conservation of mass states that matter can never be created or destroyed. -
Louis De Broglie
Discovery of the wave nature of light, his equation is E=hv.
He believed that light would form a wave-like shape motion around the proton. -
J.J Thomson, Electron
In 1897, J.J. Thomson founded the electron.
Later his colleague, Francis Ashton improved on Thomson's design of the mass spectrograph, and discovered isotopes. -
Max Planck
Came up the Quantum Theory, light is given off by hot electrons in small particles, Came up with equation E=h*f, where E=Energy in joules (J), h=Planck's constant (6.63 x 10> -34 J-s (joules per Hertz)), and f=frequency (Hertz)
Planck also came up with the photoelectric effect which states that some f of light on atoms knocks them lose.
Wave/Particle Duality, light acts like a particle when interacts with matter, light can bend (wave) , travels like a bullet (straight) -
Hantaro Nagaoka
Nagaoka presented his idea of the kinetic theor of gases and the stability of Saturns rings. This led to the question of electrons losing energy when they are not constantly moving. To prove his model correct, Nagaoka needed to prove that electrons were not losing energy. Rutherford announced an experimental test for the model of the atom, and later Bohr improved on Rutherford's tests, reinforcing Nagaoka's point. -
First Model-T Ford was built
The manufacturing of this car revolutionized the automobile industry -
Robert Millikan
Millikan used the Oil Drop experiment to find the size of an electron. -
Ernest Rutherford
Rutherford dealt with radioactive elements. He came up with the notion of half-lives. Rutherford also reported that there are two types of rays, alpha and beta rays. In 1909, Rutherford discovered the atomic nucleus and developed his atomic model. Rutherford discovered the proton and was the first to make a nuclear reaction. -
Niels Bohr
While working in the lab under the guidance of J.J. Thomson, he came up with an adequate form for the structure of atoms. He based his work on the work that Rutherford had already done. -
World War I
World War I begins -
Erwin Schrodinger
In 1926, Schrodinger discovered his wave equation. Later on he discovered the Quantum Mechanical Model, which allows one to find the most accurate location of where an electron is placed around the nucleus. The wave equation is also used to find where an electron is placed around the nucleus. Electron clouds show the most likely place for an electron to placed around the nucleus. Greater distance from nucleus, greater energy, greater number "n". The QMM replaced Bohr's Model later. -
Werner Heisenberg
All characteristics (vectors, speed, spin, mass) of a atomic or subatomic particle can not be all happening at the same time. The reason for this is that in the act of measuring some aspects of the particle, one alters another. -
James Chadwick
James Chadwick smashed an alpha particle into, beryllium. This released raditaion that was aimed into paraffin wax. The beryllium radiation hit the hydrogen atoms in the wax, and then Chadwick to the wax into a detecting chamber and massive neutral particles were discovered. These were neutrons. -
World War II
World War II begins -
Albert Einstein dies
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First Man on Moon
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Hurricane Katrina