-
500 BCE
Alchemy
It is an ancient practice. They believed that all metals are made up of mercury and sulfur. -
442 BCE
Democritus
He stated:
Matter is made of invisible particles called atoms.
Atoms are indestructible and unchangeable.
Atoms are homogenous and they don’t have an internal structure.
All atoms have different sizes and shapes. -
400 BCE
Leucippus
Worked with Democritus. Created the idea that everything is composed of various indivisible things known as an atom. -
300 BCE
Aristotle
He believed that everything was made up of four elements; fire, water, earth, and air. He said that a mass of an incomprehensible size was everywhere. He also believed that there were no different particles for each element. -
1493
Paracelsus
His idea study poison helped chemistry get introduced into the world of medicine. He helped bring the use of chemicals and minerals into medicine. -
1494
George Bauer
He made the first classification of minerals based on their physical properties. -
Robert Boyle
He believed that the elements are made up of atoms that are of different sizes that group up to make different substances. -
Antoine Lavoisier
He created the idea of the Law of Conservation. His idea stated that matter can not be created or destroyed -
Joseph Proust
Created the idea of the Law of Definite Proportions. This idea states a compound always the same elements in the same proportion of mass. -
Amadeo Avogadro
He discovered that equal volume of gas with the same temperature and pressure are equal in volume. -
Joseph Gay-Lussac
He studied the properties of gases. He created the Law of Combining Volume of Gas. He stated that equal volume of all gases expand equally with the same increase in temperature. -
John Dalton
He stated that matter is composed of atoms. All atoms are the same in size and indestructible. He believes that different elements differed in mass. Dalton's atom was similar to a billard's ball. Created the idea of the Law of Multiple Proportions. -
Jons Jakob Berzelius
He introduced the chemical system of chemical symbols. He started the idea of the periodic table. -
Crookes
He created the cathode ray tube which was used for television. His student was JJ Thomson. -
JJ Thomas
He used the Cathode Ray Tube for experiments. When he put a magnet near the beam it moved away. This experiment led up to the discovery of the electron. -
Henri Becquerel
He discovered the evidence of radioactivity. -
Robert Millikan
He determined the charge of an electron through his Oil Drop experiment. In his experiment, he took two magnetic plates that would suspend the electrons between the plates. -
Ernest Rutherford
He discovered alpha particles. His experiment called the Gold Foil experiment showed that the nucleus contains protons. -
Max Planck
He discovered the energy quanta. -
Niels Bohr
He discovered the structure of an atom. -
Louis de Broglie
Studied the electron and discovered the properties of matter. -
Werner Heisenberg
He was a pioneer in the quantum mechanics field. -
Fritz Zwicky
He discovered dark matter, which is something that makes up 30% of the universe. -
James Chadwick
He discovered the existence of the neutron. -
Murray Gell-Mann
He created the idea of the Quarks theory. Quark is the idea of combining composite particles called hadrons.
