May 31, 2020
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Atomic History, Mo and Josh
⟶ Updated 2 Oct 2017 ⟶
List of edits
23 Jan 2019
French Rev. World History
Democritus was born; In Abdera, Greece
Democritus dies; In Abdera, Greece
Democritus discovers atoms He thought the world, including human beings, is composed of very small particles called "Atomos"
All matter consists of small particles called atoms -Atoms are indestructible -Atoms are solid but invisible -Atoms are homogeneous -Atoms differ in size, shape, mass, position, and arrangement -Solids are made of small pointy, atoms -liquids are made of large round atoms -oils are made of very fine, small atoms that can slip past each other
John Dalton was born; Cumberland, England
John Dalton dies; In Manchester, England
John Dalton discovers atoms He believed every form of matter was made up of small individual particles
Experimented on gases and atmospheric pressures
The tiny particles were called atomos -Believed that atoms of different elements could be identified by their differing atomic weights -Atoms cannot be created or destroyed
JJ Thompson was born In Cheetham Hill, Manchester, United Kingdom
JJ Thompson dies Cambridge, United KIngdom
Discovered the idea of the electron of an atom
Experimented with cathode ray tube: an electrical current was passed through the tube which made a stream of particles glow showing there was something there
-Electrons have a very large charge for their mass -Electrons have a negative charge -Electrons are extremely small
Robert Millikan was born In Morrison, Illinois
Robert Millikan dies In San Marino, California
He discovers the charge of an electron, or the elementary charge
Experimented with the Oil drop: drop oil between two electrodes, measure force of droplets passing through the electrical field and the field itself, able to determine the charge of an electron
The elementary charge equaled 1.5924(17) x 10^-19 Coulombs (C) . . .
Ernest Rutherford was born In Brightwater, New England
Ernest Rutherford dies In Cambridge, United Kingdom
Rutherford discovers the nucleus, proton, and alpha/beta particles
Experimented with Gold foil: fired a beam of alpha particles through a piece of gold foil and watched as it passed through and some particles that deflected the straight path.
Atoms have a vast amount of empty space that allows any particle to pass through them .
Niels Bohr is born In Copenhagen, Denmark
Niels Bohr dies In Copenhagen, Denmark
Discovered the electron and constructed the famous Bohr model
Bohr Model: showed the atom as a positive charged nucleus surrounded by orbiting electrons.
-Electrons move around the nucleus in orbits. -Energy in atoms is quantized .
Werner Heisenberg was born In Wurzburg, Germany
Werner Heisenberg dies In Munich, Germany
Heisenberg Discovered a way to formulate quantum mechanics in term of matrices
Uncertainty Principle: states that the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa.
-Absolute causal determinism is impossible .
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