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500 BCE
Alchemy
Alchemy is a form of chemistry and speculative philosophy practiced in the Middle Ages and the Renaissance and concerned principally with discovering methods for transmuting baser metals into gold and with finding a universal solvent and an elixir of life. -
430 BCE
Democritus (460 BC - 370 BC)
Democritus was a Greek philosopher who was one of the first atomists in the Grecian tradition. He was a central figure in the development of the atomic theory of the universe. He theorized that all material bodies are made up of indivisibly small atoms. Aristotle rejected atomism in On Generation and Corruption. Aristotle refused to believe that the whole of reality is reducible to a system of atoms. As it turned out, though, Democritus was right. -
430 BCE
Leucippus (Birth Date: Unknown - 370 BC)
Leucippus originated the theory of atomism. It has been difficult to see his work because of Democritus. Parts of Leucippus writings remain and 2 books believe to have been written by him. His theory said matter is homogeneous but consists of infinity of small indivisible particles. Atoms are constantly in motion, and through collisions and regroupings form compounds. Cosmos is formed by the collision of atoms that gather together into a whirl. The Earth is located in the center of Cosmos. -
360 BCE
Aristotle (384 BC- 322 BC)
Aristotle was a Greek Philosopher and one of the first scientists in history. He made pioneering contributions to all fields of philosophy and science, he invented the field of formal logic, and he identified the various scientific disciplines and explored their relationships with each other. He also a teacher and founded his own school in Athens, known as the Lyceum. -
1522
Georg Bauer (1494-1555)
Georg Bauer is considered the founder of geology as a discipline. His work paved the way for a future stematic study of the Earth and of its rocks, minerals, and fossils. He made fundamental contributions to mining geology and metallurgy, mineralogy, structural geology, and paleo. -
1530
Paracelsus (1493-1541)
Paracelsus was a German-Swiss Renaissance physician, botanist, alchemist, astrologer, and general occultist. On his return to Europe, his knowledge of these treatments won him fame. He did not go along with the conventional treatment of wounds, which was to pour boiling oil onto them to cauterize them or to ambutate the limb, Paracelsus believed the then-ridiculous idea that wounds would heal themselves if allowed to drain and prevented from becoming infected. -
Robert Boyle (January 25, 1627- December 31, 1691)
Robert Boyle was an Anglo-Irish natural philosopher, chemist, physicist, and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of modern chemistry, and one of the pioneers of modern experimental scientific method. -
Antoine Lavoisier (August 26, 1743 - May 8, 1794)
French chemist and leading figure in the 18th-century chemical revolution who discovered the Law of Conservation of mass and the Oxygen Theory of Combustion. -
John Dalton (September 6, 1766 - July 27, 1844)
John Dalton FRS was an English chemist, physicist, and meteorologist. He found the atomic theory and researched colour blindness, sometimes referred to as Daltonism. -
Joseph Proust (September 26, 1754 - July 5, 1826)
Joseph Louis Proust was a French chemist. He was best known for his discovery of the law of constant composition which says that chemical compounds always combine in constant proportion. -
Amedeo Avogadro (August 9, 1776 - July 9, 1856)
Italian scientist, most noted for his contribution to molecular theory now known as Avogadro's law, which states that equal volumes of gases under the same conditions of temperature and pressure will contain equal numbers of molecules. -
Jons Jakob Berzelius ( August 20, 1779 - August 7, 1848)
he conducted pioneering experiments in electro-chemistry and established the law of constant proportions, which states that the elements in inorganic substances are bound together in definite proportions by weight. He is considered one of the founders of modern chemistry. -
J.J. Thomson ( December 18, 1856 - August 30, 1940)
English physicist and Nobel Laureate in Physics, credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle. -
Henri Becquerel (December 15, 1852 - August 25, 1908)
He is a French physicist who discovered radioactivity through his investigations of uranium and other substances.The SI unit of radioactivity, the becquerel (Bq), was named after him. -
Robert Millikan (March 22, 1868 - December 19, 1953)
Millikan worked on an oil-drop experiment in which he measured the charge on a single electron. He also proposed the plum pudding model, in which the electrons were immersed in a positively charged "pudding". -
Ernest Rutherford (August 30, 1871 - October 19, 1937)
He was the first to discover that atoms have a small charged nucleus surrounded by largely empty space, and are circled by tiny electrons, which became known as the Rutherford model (or planetary model) of the atom. -
Quantum Theory
Max Planck suggests that radiation is quantized
Arthur Compton discovers the quantum (particle) nature of x rays, thus confirming photons as particles.
Louis de Broglie proposes that matter has wave properties.
Niels Bohr succeeds in constructing a theory of atomic structure based on quantum ideas.
Werner Heisenberg formulates the uncertainty principle
Erwin Schroedinger develops wave mechanics, which describes the behavior of quantum systems for bosons.
