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800 BCE
The Alchemists
The Alchemists laid the foundation of the cell theory. The Alchemists attempted to purify, mature, and prefect certain materials. They thought all metals where made of sulfur. They manipulated the atom. -
430 BCE
Plato
Plato theorized that solid forms of matter are composed of indivisible elements shaped like triangles. He was a student of Socrates. -
400 BCE
Democritus
Democritus introduced the idea of the atom as the basic building block of matter. Along with that, he was born in the Ancient Greek city Abdera. -
Robert Boyle
Robert Boyle demonstrated matter is composed of tiny particles he called corpuscles. Corpuscles (also known as atoms) make up all substances according to Boyle. Boyle was born the 25th of January, 1627. -
Antone Lavoisier
Antone Lavoisier defined the law of conservation of mass. He was born on August 26th, 1743. -
Billiard Ball Model
John Dalton created the Billiard Ball Model which proposed atoms were small, hard spheres with no internal parts. -
John Dalton
John Dalton suggested all matter was comprised of indivisible and indestructible atoms with distinct masses and properties. Dalton had a mild stroke at the age of 71. -
Amedeo Avogadro
Avogadro proposed equal gas volumes contain equal numbers of molecules under the same conditions of temperature and pressure. He was born August 9th 1776. -
Dmitri Mendeleev
Mendeleev discovered the periodic table. He was awarded the Copley Medal in 1905. -
JJ Thomson
Thomson proposed a model for the structure of an atom. He was born December 18th, 1856. -
Plum Pudding Model
JJ Thomson created the Plum Pudding Model in 1904. He showed that electrons were embedded in a uniform sphere of positive charge. He referred this to blueberries attached to a muffin. -
Albert Einstein
Einstein mathematically proved the existence of atoms. He didn’t pass his college entrance exam but is considered one of the smartest people to have lived. After he died, the stole his brain to research it! -
Robert Millikan
Robert Millikan precisely determined the magnitude of the electron’s charge. He was born in 1868 on March 22nd. -
Ernest Rutherford
Rutherford discovered atoms contain a positively charged nucleus much caller than the actual atom. He was born August 30th 1871. -
Neils Bohr
Neils Bohr explained how electrons moved around the nucleus of an atom. Bohr liked soccer and even played on a college soccer team. -
Henry G.J. Mosely
Mosely reported the frequencies are proportional to the squares of whole numbers equal to the atomic number plus the constant. He was born November 23rd, 1887. -
Solar System Model
Neils Bohr proposed electrons are arranged in concentric circular orbits around the nucleus. The model is patterned on the solar system and known as the planetary model. -
Werner Heisenberg
Heisenberg formulated a type of quantum mechanics based on matrices. He died in Munich Germany. -
Electron Cloud Model
Erwin Schrödinger and Werner Heisenberg created the Electron Cloud Model tool for visualizing most likely electron positions in an atom. -
Erwin Schrödinger
Scrödinger combined equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons of an atom. He was born August 12th, 1887. -
James Chadwich
James Chadwich Proved the existence of neutrons. He died at age 82 in 1974. -
Pierre and Marie Curie
The Curies where a married couple exploring science. The found that radioactivity does not depend on how atoms are arranged into molecules, but rather that it originates within the atoms themselves. Because of all the radiation exposure, Marie Curie died by radiation. However, Pierre died by his skull getting crushed by a horse drawn carriage.