Atomic Theory Timeline

Great Wall Of China

221

During the Qin Dynasty, construction of the Great Wall of China begins.

Eratosthenes Measure the Earth's Circumference

276

or so he thought.

Democritus

300

Said that if you cut something in half again and again, there will come a point that you cannot cut it in half anymore. He said that it was invisible, which in greek is atomos. Thus, the theory of the atom was born.

Aristotle

300

Beleived that everything in the univers was made up of four elements. Air, Fire, Earth and Wind.

Invisible Model

300

Democritus thought that the atom was an invisible force that held everything togeather.

Muhammad

Dec 18, 610

Begins preaching in Mecca

First Windmill

Dec 18, 1180

Was constructed in Norway

Columbus

Dec 18, 1492

He indeed discovered America

Isaac Newton

Feb 1, 1704

Came up with the idea of small solid masses in motion in a mechanical universe.

Rudjer Josip Boscovic

Dec 18, 1738

Internal spatial coordinates are used instead of external coordinates. Boscovich's theory is kinematic rather than dynamical. It uses only two-dimensional quantities rather than the three used by Newton.

Joseph Priestly

Dec 18, 1754

Best known for his discovery of oxygen (i giggled a little at that one) he was able to isolate it and identify it.

Great Britain and Ireland

Dec 18, 1801

Merged to become the United Kingdom

John Dalton

Oct 19, 1803

Atoms are the smalles part of the element. Atoms of the same element have the same atomic mass. The ratio of the masses of the bonded elementes will always be a definite whole-number proportion.

Small, Spherical,Solid Model

Dec 18, 1808

Developed by Dalton. Thought that the atom was shaped like this.

Antarctica was discovered

Dec 18, 1820

Michael Faraday

Aug 21, 1832

Studied the effect of electricity on solution, coined term "electrolysis" as splitting molecules with electrisity, developed laws of electrolysis. Faraday himself was not a proponent of atomism.

First telegraph

Dec 18, 1844

line was connected in the world between Baltimore and Washington

J. Plucker

Dec 18, 1859

Built one of the first gas discharge tubes. Also known as a Cathode Ray Tube.

Asprin was discovered

Dec 18, 1889

First commercial film was released

Dec 18, 1894

Wilhelm Roentgen

Dec 18, 1895

Discovered X-rays

Henri Becquerel

Dec 18, 1896

Found that if uranium was left on a photographic plate without any light, the ore would leave an image.

Olympic Games revived in Greece

Dec 18, 1896

JJ Thomson

Dec 18, 1897

Discovered the electron, and put forward a theory that the atom was made up of smaller particles. He proved this theory using the cathode ray tube.

Plum Pudding Model

Dec 18, 1897

J.J. Thompson developed this model. He described the atom to be a mixture of positivly and negativly charged particles mixted togeather.

Soddy

Dec 18, 1900

Observed spontaneous disintegration of radioactive elements into variants he called "isotopes" or totally new elements, discovered "half-life", made initial calculations on energy released during decay.

Marie Curie

Dec 17, 1902

discovered new elements and conducted radiation test to understand how the elements reacted.

Russia Japan War

Dec 18, 1904

Ethiopia decleared independence

Dec 18, 1906

Sicily earthquake kills tens of thousands

Dec 18, 1908

Ernest Rutherford

Dec 18, 1911

Discovered the atom to be made up of a positive, solid core and an orbiting mass of electrons and neutrons. He did so by experimenting with a gold foil and an infinite particle emitter.

Niels Bohr

Dec 17, 1913

His atomic theory was a combo of Rutherford's work and Planck's Quantom theory. Bohr proposed that the outer orbits could accommodate more electrons than the inner orbits

Planetary Model

Dec 18, 1913

Neils Bohr founded the model, he thought that the electrons orbited the positivly charged nucleus like the planets orbit the sun.

Irish free state established

Dec 18, 1922

Werner Heisenberg

Dec 17, 1925

Invented matrix mechanics, the first version of quantom mechanics. He extended this to complete a mathimatical theory of the behavior of atoms and their constituents.

Electron Cloud Model

Dec 18, 1925

Werner Heisenberg found that the electrons just occupy a general area of space around the central positive nucleus.

Erwin Schrodinger

Dec 18, 1926

Set a foundation for wave-mechanics approch to quantum theory.

New York stock market crash

Dec 18, 1929

James Chadwick

Dec 17, 1932

Provided the existance of neutons as uncharged particles in atoms.

NATO established

Dec 18, 1949

Robert Millikan

Dec 18, 1990

Discovered the charge on an electron during the Oil Drop Experiment

The Social War

Dec 18, 1991

Revolt of the Italians who wanted Roman Citizenship.

Social War

Dec 18, 1991

Revolt of Italians who wanted Roman Citizenship

World Trade Center Towers Collapsed

Sep 11, 2001

Barack Oboma Elected president of the US

Dec 19, 2008

Gunman assults Conn. elementary school, 27 dead

Dec 13, 2012