The History of the Atom by Hayley

Aristotle

384

Aristotle was born in Stagira, Greece. He said that all subtances are made of 4 elements. They are Earth, fire, water, and air. In 322 he died.

Democritus

400

Democritus was born in Abdera, Greece. He was the scientist who proposed the idea of the atom. His theory was that the universe was made up of two elements. He was never married and loved to travel .At 90 years old he died.

John Dalton

Sep 6, 1766

Dalton was born on September 6, 1766. His atomic theory was that matter is made up of tiny particles called atoms. He died on July 27 1844.

J.J. Thomson

Dec 18, 1856

J.J. Thomson was born on December 18, 1856. He discovered electrons and also conducted the Cathode Ray Tube experiment. He died on August 30, 1940.

Robert Millikan

Mar 22, 1868

Robert Millikan was born on March 22,1868. He determined the charge and weight of the electron. He also conducted The Oil Drop Experiment. He died on December 19, 1953.

Ernest Rutherford

Aug 30, 1871

Ernest Rutherford was born on August 30, 1871. He conducted the Gold Foil Experiment in which he concluded that the atom is made mostly out of empty space. He also concluded that the atom contains a posititvely charget piece at its center. He died on October 19, 1937.

Niels Bohr

Oct 7, 1885

Niels Bohr was born On October 7, 1885. he proposed that an electron is only found in certain circular paths. He died on November 18, 1962.

Sir James Chadwick

Oct 20, 1891

Sir James Chadwick was born on October 20, 1891. He confirmed the existence of neutrons in the nucleus. He died on July 24, 1974.