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384 BCE
Aristotle
Aristotle is a towering figure in ancient Greek philosophy, who made important contributions to logic, criticism, rhetoric, physics, biology, psychology, mathematics, metaphysics, ethics, and politics. He was a student of Plato for twenty years but is famous for rejecting Plato's theory of forms. Aristotle laid the philosophical groundwork for all subsequent discussions of elements, pure substances, and chemical combination. -
370 BCE
plato
Plato was an ancient Greek philosopher born in Athens during the Classical period. In Athens, Plato founded the Academy, a philosophical school where he taught the philosophical doctrines that would later become known as Platonism -
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. -
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. -
robert boyle
Robert Boyle FRS was an Anglo-Irish natural philosopher, chemist, physicist, alchemist 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. -
john dalton
John Dalton FRS was an English chemist, physicist and meteorologist. He is best known for introducing the atomic theory into chemistry, and for his research into colour blindness, which he had. Colour blindness is known as Daltonism in several languages, being named after him. -
Newland's law of octaves
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. -
Robert Milikan
Robert Andrews Millikan was an American experimental physicist who won the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric effect. Millikan graduated from Oberlin College in 1891 and obtained his doctorate at Columbia University in 1895. -
Mendeleev's pd. table
The periodic table, also known as the periodic table of the elements, arranges the chemical elements into rows and columns. It is an organizing icon of chemistry and is widely used in physics and other sciences -
the photoelectric effect
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. -
discovery of radioactivity
Radioactivity is the release of energy from the decay of the nuclei of certain kinds of atoms and isotopes. Atomic nuclei consist of protons and neutrons bound together in tiny bundles at the center of atoms. -
plum pudding model
The plum pudding model depicts the electrons as negatively-charged particles embedded in a sea of positive charge. The structure of Thomson's atom is analogous to plum pudding, an English dessert (left). -
Planck's quantum theory of light
Planck proposed that the energy of light is proportional to frequency, and Planck's constant (h) is the constant that relates them. Albert Einstein determined that light is made up of discrete quanta of energy called photons as a result of his research. -
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. Some particles had their paths bent at large angles. -
Bohr's planetary model
the electrons encircle the nucleus of the atom in specific allowable paths called orbits -
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 discovery of the proton is credited to Ernest Rutherford, who proved that the nucleus of the hydrogen atom (i.e. a proton) is present in the nuclei of all other atoms in the year 1917. Based on the conclusions drawn from the gold-foil experiment, Rutherford is also credited with the discovery of the atomic nucleus. -
Heisenberg Uncertainty 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; the more we nail down the particle's position, the less we know about its speed and vice -
discovery of the neutron
In May 1932 James Chadwick announced that the core also contained a new uncharged particle, which he called the neutron. Chadwick was born in1891 in Manchester, England. -
Schrodinger equation
The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. -
the alchemists
The Alchemist is a novel by Brazilian author Paulo Coelho which was first published in 1988. Originally written in Portuguese, it became a widely translated international bestseller