-
460 BCE
Democritus
Developed classical atomism, theorized that particles of matter moved through empty space. -
322 BCE
Aristotle
Recognized that ordinary material things are composed of multiple substances. -
400
Alchemists
Ancient art form that people used who believed they could turn any substance into gold, prolong life and cure illness. -
Robert Boyle
Discovered Boyle's law, states that the volume of a gas decreases with increasing pressure and vice versa. -
American Revolution
-
John Dalton
Dalton invented the standard unit for atomic mass, the Dalton. -
American Civil War
-
Thomson's Experiment
He conducted the Cathode Ray Tube experiment, and discovered electrons. -
Dmitri Mendeleev
Mendeleev is considered to be the most important contributor to the periodic table, as he arranged them in groups based on similarities. -
Rutherford's Experiment
Rutherford shot a beam of tiny particles at a sheet of gold foil, and discovered most of the space in an atom is empty -
Geiger's Experiment
Geiger invented the Geiger Counter which is a device used for counting atomic particles. -
Milikan's Experiment
Milikan conducted the oil drop experiment, proved that there was a smallest unit of charge. -
Niels Bohr
Proposed a theory for the Hydrogen atom that electrons should move around the nucleus in prescribed orbits. -
World War 1
-
World War 2
-
Hiroshima