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Jan 1, 1000
Democritis
Developed the idea of an atom. Conceived the idea that matter was made up of minuscule, irreducible particles, which he called atoms, a name derived from the Greek word atomos, meaning indivisible. (460 B.C.) -
Jan 1, 1000
Aristotle
(322 B.C.) Claimed that there was no smallest part of matter (atoms) and that different substances were made up of proportions of fire, air, earth, and water. -
Antonie Lavosier
Came up with the Law of Conservation of Mass. -
Joseph Proust
Proposed the Law of Constant Composition. -
Dalton
Stated that all matter is made of indivisible and indestructible atoms, which differ from element to element.The atom, it was assumed, was of uniform density and constitution. Discovered the Dalton theory. Law of Multiple Proportions. -
Invention of the Light Bulb
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Amadeo Avogadro
Avogadro's Hypothesis. The hypothesis states that at the same temperature and pressure, equal volumes of gases contain the same number of molecules or atoms -
Invention of the First Camera
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The Invention of the Telephone
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William Crookes
Discovered cathode-ray tubes. -
First Car was Invented
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First Tractor was Invented
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Invention of the Radio
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J.J. Thompson
Discovered the electron. -
Madam Curie
Stated that radioactive materials cause atoms to break down spontaneously, releasing radiation in the form of energy and subatomic particles. -
Henri Becquerel
Discovery radioactivity along with Madame Curie. -
Invention of the First Vacuum
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Max Planck
Stated that energy is radiated in small, discrete units, which he called quanta. -
Albert Einstein
The existence of atoms of finite size -
Robert Millikan
Calculated mass of a single electron -
Rutherford
Found evidence that the atom really consisted of a highly dense nucleus and a vast empty space in which the electrons orbited. -
Henry Moseley
The atomic number was equal to the positive charge (charge on the nucleus) of an atom. -
Niels Bohr
Created Bohr Model. -
Louis deBrogile
Suggested matter consists of waves. -
Invention of the T.V.
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Erwin Schrodinger
Schrödinger model. Explained movement of an electron in an atom as a wave. -
Werner Heisenberg
Uncertainty Principle, which says that the more precisely the position of a particle is determined, the less precisely the momentum is known in this instant, and vice versa. -
James Chadwick
Proved that neutrons, neutral particles in the nucleus that made up approximately half the mass of an atom, did exist -
Invention of the Computer
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Invention of the DVD Player
