Jan 28, 999
What: He created earliest ideas of atoms, thinking everything was made up of only 4 substances.
When: 500 BC
How: He told people his theories.
Sep 6, 1010
AristotleWho: Aristotle (Greek)
When: 2,500 years ago
What: Aristotle believed that everything was made from natural elements like air, water, fire, and earth.
How : Told people about his theories.
Isaac NewtonWho: Isaac Newton (English)
When: Born January 4, 1643
What: Newton realized that atoms had a neutral electrical charge overall, but could also have their energy levels distorted. Though, this was not accurately proven untill the 1930's
How: Isaac did his experiments mentally.
John DaltonWho: John Dalton (English)
When: Born on September 6, 1766
What: Figured out that gases are made out of individual particles
How: Did different experiments involving air and water mixtures.
Max PlanckWho: Max Planck (German)
When: Born April 23, 1858
What: Originator of Quantum Theory. Used this to explain glowing matter.
How: Made his point by using mathematics.
Hantaro NagaokaWho: Hantoro Nagaoka (Japanese)
When: Born August 15, 1865
What: Had the idea that atoms may have a central nucleus and that electron move like the rings around Saturn.
How: Saturnian Model (it was an early model, comparing the rings of Saturn to electron movements).
Ernest RutherfordWho:Ernest Rutherford (English)
When: Born August 30, 1871
What: Discovered uranium has a positive charge.
How: He deflected light rays as his experiment. He used a radioactive source and right across put a piece of gold foil. On the outside, he placed a fluorescent screen to see where the light reflected. This provided evidence that atoms have a negative/positive charge.
Niels BohrWho: Niels Bohr (Danish)
When: Born in Denmark on October 7, 1885
What: A Nobel Physics Prize winner, he figured out electrons can't exsist between energy levels.
How: Drew a model.
Erwin SchrodingerWho: Erwin Schrodinger
When: August 12, 1887
What: Erwin understood the motions of electrons in atoms.
How: He did mathmatical equations.
Ernest MarsdenWho: Ernest Marsden (British)
When: Born Febuary 19,1889
What / How: He was the student of Rutherford. They tested out the same experiments and had the same types of theories.
James ChadwickWho: James Chadwick (British)
When: October 20, 1891
What: Confirms the exsistence of neutrons.
How: He hit paricles together, and let the radiation bounce off into pariffin wax. The parts left behind are neutrons.
Louis de BroglieWho: Louis de Broglie (French)
When: Born August 25, 1892
What: Thought that moving particles have properties of waves.
How: Did a multitude of experiments.
JJ ThomsonWho: JJ Thomson (British)
When: On December 11, 1906 Thomson won the Nobel Prize in Physics.
What: Created the atomic model known as "Plum Pudding". He believed that atoms had a negative and positive charge.
How: Thomson made a model using electric curent source, metal disks, a sealed tube filled with gas at low pressure, and a glowing beam. When the device is turned on, on disk has a negative current the other a positive, This provided evidence that atoms have a negative/positive charge.