HISTORY OF THE ATOM

DEMOCRUTIS

• Lived around 460 BC in Abdera
• Was not the first to propose the theory, but adopted it developed it further, and provided a more detailed and systematic view of the physical world.
• Took a seashell and broke it until it became powder, and discovered that atoms pack together.
• Studied under Leucippus
• Known as "the laughing philosopher"

JOHN DALTON

• Live 1766-1884 in England
• Atomic Theory
• Experimented with gases
• Chemist
• Physcist
• Meteorologist

ERNEST RUTHERFORD

• Lived in 1871 in several countries, including New Zealand and Canada
• The first to split an atom
• Won a Nobel Prize in Chemistry
• Studied X-rays

NIELS BOHR

• Lived in 1885 in Denmark and Copenhagen
• Came up with a theory for atomic structure
• Studied energy levels
• Won a Nobel Prize in 1922 in Physics

ANTOINE LAVOISIER

• Lived in 1743 in Paris, France
• Found chemical reactions in atoms
• Contributed to chemical revolution
• Large influence in Chemistry

J.J. THOMSON

• Lived in 1856 in the U.K.
• Discovered the electron
• Demonstrated cathode rays are negatively charged
• English Physicist

ROBERT MILLIKAN

• Lived in 1868 in the U.S.
• Was able to measure the charge of the electron
• Won a Nobel Prize for physics
• Able to obtain the exact value of Planck's constant

JAMES CHADWICK

• Lived in 1891 in Bollington
• Discovered the neutron
• Won the 1935 Nobel prize in physics
• Smashed an alpha particle into beryllium, a metallic element. This then released radiation that was aimed into paraffin wax. The beryllium radiation hit the hydrogen atoms that were in the wax. Chadwick then took the wax into a detecting chamber and massive neutral particles were discovered. Named these particles neutrons.

SOURCES

• "Democritus." Ancient History Encyclopedia. N.p., n.d. Web. 26 Jan. 2016.
• "John Dalton." John Dalton. N.p., n.d. Web. 26 Jan. 2016.
• Bio.com. A&E Networks Television, n.d. Web. 26 Jan. 2016.