Atomic Theory

Scitentists and their contribution

John Dalton

1803

Proposed the atomic theory. Stated that all matter was composed of small indivisible particles called atoms, atoms of a given element possess unique characteristics, and three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).

Eugen Goldstein

1886

Discovered that atoms have positive charges.

J.J. Thompson

1897

Discovered the electron.

Max Planck

1900

Announced idea that energy emitted by a resonator could only take on discrete values, with v being the energy for a resonator of frequency in hv, and h being the universal constant, now known as Planck’s constant.

Robert Millikan

1910

Used the falling drop method to accurately determined the charge of an electron

Ernest Rutherford

1911

Rutherford model of atom which explained that a small positively-charged nucleus was orbited by electrons.

Neils Bohr

1913

Published model of the atomic structure. Became basis of the quantum theory.

Henry Moseley

1913

Discovered systematic relation between wavelength and atomic number. Now known as Moseley’s Law.

Albert Einstein

1915

Proposed special theory of relativity. States that matter and energy are one through the formula E=mc squared.

Louis deBroglie

1924

Discovered wave nature of electrons and suggested that all matter have wave properties.

Erwin Schrodinger

1926

Discovered Schrodinger wave equation which stated that the quantum state of a physical system changes over time.

Werner Heinsenberg

1927

Proposed the uncertainty principle. States that you cannot determine the position and velocity of a subatomic particle at the same time.

James Chadwick

1932

Discovered the neutron.

Other contrabuitions

Joseph Priestly

1774

Discovered oxygen

Allesandro Volta

1775

Invented the electrophorus.

Antoine Lavoisier

1785

Discovered law of conservation of mass.

Michael Faraday

1831

Discovered induction of electric currents and constructed first electric dynamo.

Louis Pasteur

1857

Discovered pasteurization process.

Alfred Nobel

1867

Obtained patent for dynamite.

Henri Bequerel

1896

Discovered natural radioactivity.

Marie Curie

1898

Discovered polonium and radium.

Guglielmo Marconi

1901

Proved that wireless waves were not affected by the curvature of the Earth.

Sir Frederick Banting

1922

Discovered insulin.

Philo Farnsworth

1927

Produced the first television transmission.

Wallace Carothers

1931

Created nylon, a synthetic replacement of silk.

Leo Szilard

1942

Created first successful controlled nuclear chain reaction.

Kary Mullis

1983

Developed polymerase chain reaction.

Siginificant history events

Discovery of the Americas

1421

Discovered by Chinese Admiral Cheng Ho

Gutenberg Printing Press

1445

Reformation of the Catholic Church

1527

Galileo Convicted of Heresy

1632

The Declaration of Independence is Signed

1776

Civil War

1861 - 1865

First Transcontinental Railroad is Finished

1869

Archduke Francis Ferdinand is Assassinated

1914

event that sparked WWI

Bolshevik Revolution

1917

Treaty of Versailles

1919

ended WWI

Bombing of Pearl Harbor

1941

Japans attack againsted U.S. durring WWII

First Recorded Social Interaction Through Networking

1962

First Cellular Phone

1973