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384 BCE
Aristotle
Aristotle was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato. -
370 BCE
Democritus
Democritus was an Ancient Greek pre-Socratic philosopher from Abdera, primarily remembered today for his formulation of an atomic theory of the universe. None of his work has survived. -
348 BCE
Plato
Plato was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy -
500
The Alchemists
alchemists sought to manipulate the properties of matter in order to prepare more valuable substances -
Lavoisier
Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) -
john dalton
John Dalton FRS was an English chemist, physicist and meteorologist. He is best known for introducing the atomic theory into chemistry -
newtons law of Octaves
Newland's Law of Octaves states that when Elements are arranged in increasing order of Atomic Mass, the properties of every eighth Element starting from any Element are a repetition of the properties of the starting Element. -
Mendeleev's Pd. Table
Mendeleev claimed the famous periodic law that “Element properties are a periodic function of their atomic weight.” Mendeleev placed elements in the order of their atomic weights in the form of a table known as the Periodic Table of Mendeleev. -
Photoelectric effect
phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation. The effect is often defined as the ejection of electrons from a metal plate when light falls on it. -
discovery of radioactivity
March 1, 1896: Henri Becquerel Discovers Radioactivity. In one of the most well-known accidental discoveries in the history of physics, on an overcast day in March 1896, French physicist Henri Becquerel opened a drawer and discovered spontaneous radioactivity. -
discovery of the electron
During the 1880s and '90s scientists searched cathode rays for the carrier of the electrical properties in matter. Their work culminated in the discovery by English physicist J.J. Thomson of the electron in 1897. -
Planck's quantum Theory of light
Planck's quantum theory of fussy light tells us that light bulb filaments should be heated to a temperature of about 3,200 Kelvin to ensure that most of the energy is emitted as visible waves. Much hotter, and we'd start tanning from the ultraviolet light. -
plum pudding model
The plum pudding model (also known as Thomson's plum pudding model) is a historical scientific model of the atom. The plum pudding model is defined by electrons surrounded by a volume of positive charge, like negatively-charged “plums” embedded in a positively-charged “pudding” (hence the name). -
Rutherford's gold foil experiment
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. -
Bhor's Planetary Model
The Bohr Model is a structural model of an atom. The model was proposed by physicist Niels Bohr in 1913. In this model, the electrons travel around the nucleus of an atom in distinct circular orbits, or shells. The model is also referred to as the planetary model of an atom. -
Mosley's Atomic Numbers
In 1914 Moseley published a paper in which he concluded that the atomic number is the number of positive charges in the atomic nucleus. He also stated that there were three unknown elements, with atomic numbers 43, 61, and 75, between aluminum and gold. -
discovery of the proton
The proton was discovered by Ernest Rutherford in the early 1900's. During this period, his research resulted in a nuclear reaction which led to the first 'splitting' of the atom, where he discovered protons. He named his discovery “protons” based on the Greek word “protos” which means first. -
Charge of the electron
Electrons have an electric charge of −1 and their mass is approximately about 1/2000 the mass of a neutron or proton. Electron charge is usually denoted by the symbol e. It is a fundamental physical constant that is used to express the naturally occurring unit of electric charge which is = 1.602 × 10-19 coulomb. -
Schrodinger Equation
The Schrodinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the subject. -
heisenberg uncerainty principle
Formulated by the German physicist and Nobel laureate Werner Heisenberg in 1927, the uncertainty principle states that we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy -
Discovery of a neutron
The British physicist Sir James Chadwick discovered neutrons in the year 1932. He was awarded the Nobel Prize in Physics in the year 1935 for this discovery. It is important to note that the neutron was first theorized by Ernest Rutherford in the year 1920. -
Robert millikan
an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric effect.