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500 BCE
Leucippus
He was the earliest Greek to develop the theory of atomism. Believed that atoms had space between each other, and that they were completley solid -
400 BCE
Aristotle
Believed everything was made up of air, water, Earth and fire. -
400 BCE
Democritus
Came up with the first atomic theory, but he had no evidence -
1530
Paracelsus
He was a physician, alchemist, and astrologer. He emphasized the value of observation. -
1556
George Bauer
Studied the closely related techniques of mining and metallurgy. Wrote books about his findings. -
Alchemy
the medieval forerunner of chemistry, based on the supposed transformation of matter. -
Robert Boyle
The founder of modern chemistry, and one of the inventors of modern scientific method. Came up with Boyle's law. Boyle's law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within a closed system. -
Antoine Lavoisier
Came up with the law of conservation of mass. Had large influences on both chemistry and biology. He was the first person to make good use of the balance. Studied the burning process. -
Joseph Proust
Came up with the law of definite proportion. It meant that in all cases, the masses of one element that combine with a fixed mass of another element while forming a compound with small whole number ratios. -
John Dalton
Came up with the first tested and proved atomic theory. He also came up with the law of multiple proportions.
He believed that:
1. All matter is made of atoms
2. All atoms of the same element are identical
3. Atoms of different elements are different
4. Compounds are formed by chemically combining atoms
5. Atoms are indivisible -
Jons Jakob Berzelius
One of the founders of modern chemistry. he was one of the first scientists to accept John Dalton's atomic theory. -
Joseph Gay-Lussac
Know for his work on alcohol-water mixtures. Studied extensive investigations of how the volume of various gases changes with temperature changes. -
Amadeo Avogadro
Contributed to the molecular theory. He contibution was called Avogadro's law, and it states that equal volumes of gases under the same conditions of temperature and pressure will contain equal numbers of molecules. -
J.J. Thomson
Discovered the electron. Invented the Plum Pudding model. Invented the Crookes tube experiment.
1. The pinwheel cast a shadow. This meant the beam had energy
2. The beam moved to the left, the pinwheel moved to the right. This meant the beam had particles.
3. Took pinwheel out and put a magnet on top. The beam moved away from the negative magnet. The particles are negative. -
Henri Becquerel
The first person to discover evidence of radioactivity. He discovered that some invisible radiation had been emitted from uranium. -
Robert Millikan
Got the Nobel Prize. Came up with the oil drop experiment. He put oil drops between two magnetic plates, he used this to measure the charge of electrons -
Ernest Rutherford
The father of Nuclear Physics. Invented the Gold foil experiment.
1. Most of the alpha particles went straight through the gold foil. Atoms are mainly empty space.
2. Some alpha particles got deflected, Very dense, with a small nucleus
3. Sometimes the alpha particles came straight back. Hit something in the nucleus that was positively charged. -
Max Planck
A German theoretical physicist whose discovery of energy quanta. He was the originator of the quantum theory of energy. His work contributed to the understanding of atomic and subatomic processes. -
Niels Bohr
A Danish physicist who made contributions to understanding atomic structure and quantum theory. -
Arthur Compton
Discovered the Compton effect. The Compton effect is the scattering of a photon by a charged particle, usually an electron. -
Louis de Broglie
A French physicist who made contributions to quantum theory. He discovered the wave nature of electrons and suggested that all matter have wave properties. -
Werner Heisenberg
A German theoretical physicist and one of the key pioneers of quantum mechanics. -
Erwin Schrodinger
He was an Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave mechanics. He formulated the wave equation. -
James Chadwick
Discovered the neutron. The neutron wasn't discovered until then because they were hard to find, and they had no charge. Discovered a nucleus had protons (Positive, 1 amu), and neutrons (neutral, 0 amu). Also discovered isotopes. Isotopes are atoms of the same element with different mass, or number of neutrons. -
Murray Gell-Mann
Worked on the theory of elementary particles. He is credited with the introduction of the concept of quarks. A quark is any of a number of subatomic particles carrying a fractional electric charge, postulated as building blocks of the hadrons. -
Carol Rubbia
He was an Italian particle physicist and inventor. Discovered the massive, short-lived subatomic W particle and Z particle. These particles are the carriers of the so-called weak force involved in the radioactive decay of atomic nuclei. The existence of these particle confirms the electroweak theory. -
Peter Higgs
Discovered the existence of the Higgs particle. Worked on the mass of subatomic particles.
