-
428 BCE
Plato
Plato was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He introduced the atomic theory in which ideal geometric forms serve as atoms, according to which atoms broke down mathematically into triangles. -
400 BCE
Democritus
Democritus was one of the two founders of ancient atomist theory. -
384 BCE
Aristotle
Aristotle was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, Aristotle did not believe that matter was made up of tiny particles called atoms. -
John Dalton
John Dalton was an English chemist, physicist and meteorologist. He is best known for introducing the atomic theory into chemistry, and for his research into color blindness, which he had. Color blindness is known as Daltonism in several languages, being named after him. -
Laviosier
Laviosier did work in defining the law of conservation of mass, he reacted oxygen with inflammable air, obtaining "water in a very pure state" -
The Alchemists
They do secretive experiments, usually involving heat and the mixture of liquids, led to the development of pharmacology and the rise of modern chemistry. -
Discovery of the proton
the discovery of the proton was founded by William prout, and he suggested that all atoms are made up of hydrogen atoms (which he referred to as protyles). When canal rays (positively charged ions formed by gases) -
newtons law of octaves
it was founded by john Newlands, and it is that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements. -
Mendeleev's pd. Table
the Mendeleev's pd. Table was discovered by John Newlands, and he realized that the physical and chemical properties of elements were related to their atomic mass in a "periodic" way and arranged them so that groups of elements with similar properties fell into columns in his table. -
photoelectric effect
the photoelectric effect was founded by Heinrich Rudolf Hertz., the phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. This effect is often defined as the ejection of electrons from a metal plate when light falls on it. -
Discovery of Radioactivity
the discovery of radioactivity was discovered by Henri Becquerel, and when his experiment "failed" because it was overcast in Paris. For some reason, Becquerel decided to develop his photographic plates anyway. To his surprise, the images were strong and clear, proving that the uranium emitted radiation without an external source of energy such as the sun. Becquerel had discovered radioactivity. -
Discovery of the electron
the discovery of the electron was discovered by J.J. Thomson, During the 1880s and ’90s scientists searched cathode rays for the carrier of the electrical properties in matter. -
Planck's Quantum Theory of light
Accoriding to Plancks quantum theory, different atoms and molecules can can emit or absorb energy in discrete quantities only, discovered by Max Planck. -
Plum Pudding Model
the plum pudding model was discovered by J.J. Thomson, the plum pudding model has electrons surrounded by a volume of positive charge, like negatively charged "plums" embedded in a positively charged "pudding" -
Robert Millikan
Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil drop experiment, he charged droplets of oil between two electrodes and balanced the gravitational force with upward forces. -
Rutherfords gold foil experiment
the rutherfords gold experimnt was discovered by Ernest Rutherford, it was a piece of gold foil was hit with alpha particles, which have a positive charge. Most alpha particles went right through. This showed that the gold atoms were mostly empty space. -
Bohr's Planetary model
it was founded by Niels Bohr, and it was description of the structure of atoms, especially that of hydrogen, proposed (1913) by the Danish physicist Niels Bohr. -
Mosley's Atomic Numbers
henry mosley published a paper in which he concluded that the atomic number is the number of positive charges in the atomic nucleus. -
charge of the electron
Robert millikan discovered charge of the electron and won noble prize in physics in 1923 -
Schrodinger Equation
The schrodinger equation is a linear partial differential that governs the wave function of a quantum-mechanical system. -
Heisnberg Uncertainty Principle
The Heisnberg Uncertainty Principle was fo0unded by Werner Heisenberg, what it is that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory. The very concepts of exact position and exact velocity together, in fact, have no meaning in nature. -
Discovery of the neutron
the neutron was discovered by James Chadwick, he announced that the core also contained a new uncharged particle, which he called the neutron. Chadwick was born in1891 in Manchester, England.
