Dicovery of Atomic Theory

Concept of the Atom presented

450

Democritus and Leucippus first introduced the concept of the atom in 450 B.C.
They used greek philosophy and decided that the concept could work.

Athens

450

The Theseus Temple was complete in Athens in this year.

Philippine Revolution

Jan 1, 1897

Philippine revolution is finnaly quelled by Spanish, Large factor in U.S.'s involvement in Spain's foreign affairs. Spanish-American War is on the verge.

Discovery that atoms have electrons

Apr 30, 1897

JJ Thomson discovered using cathode rays, saying that since they could travel so fast that they must weigh as much as what they are made up of which he said were negatively charged particles called electrons. One of the ways he explained this was using the Plum Pudding model. The model explained that electrons were dispersed equally over a positive field. He won the Nobel Prize for Physics in 1906.

Discovery of Protons and Neutrons

Mar 12, 1911

After he discovered the nucleus Erenst Rutherford named the particles that made up the nucleus protons for the positive particles and neutrons for the particles that had no charge.

Discovery that Atoms have a nucleus

Mar 12, 1911

Ernest Rutherford discovered that atoms have a positively charged center called a nucleus. He discovered this using his gold foil experiment when he shot a beam of aplha particles at the foil and expected most to go straight through, but what happend was that some particles shot off in several different directions which led to his theory that all atoms have a small positively charged center called a nucleus. He was a student under JJ Thomson.

Theft of the Mona Lisa

Aug 11, 1911

The theft of the Mona Lisa is discovered the morning of April 11th. The Louvre is devisated.

16th Amendment

Feb 3, 1913

The 16th Amendment is ratified on this day fully accepting it.

Discovery of energy levels

Sep 12, 1913

He stated the theory that electrons orbited in precisce patterns around the nucleus and that the different electrons travelled in shells independent from each other. The model was later called the Bohr model of the atom. He won the Nobel Prize in Physics in 1922.

Women's Movement

Oct 1, 1913

During this time period, Women's Suffrage had just rolled out as a largelry world wide progressive movement. Although this had little to do with Science, many women scientists had a hand in contributing to this cause.

Discovery of electron orbitals

Oct 17, 1922

In automn of 1922 Erwin Schrodinger reexamined the Bohr-Sommerfield model of the atom and using geometric ideas he calculated the patters or orbital that elcetrons travel in. He also later created the famous Schrodinger's cat experiment.