Kyle's timeline of scientist

Democritis

Oct 28, 1000

He believed that all mater consist of extremely small particles that could not be divided. As philosihers he came up with his own ideas, and thoughts.

Aristotle

Oct 28, 1000

He did not think that there was a limit to the number of times matter could be divided. As a philosipher he came up with his own theories.

Joseph Proust

Oct 31, 1754

Made the law of definite proportions. Mixed chemical substences to suport the law of definite proportions. Died in 1826

John Dalton

Oct 30, 1766

Developed a theory to explain why the elements in a compound always join in the same way. To prove this theory he measured the masses of elements that combine when compounds form.

J.J. Thomson

Oct 28, 1856

He hypothesized that the beam was a stream of charged particles that interacted while the air in the tube caused the air to glow. He used an electric current to learn more about atoms. He was born in 1856 and died in 1940.

Robert Milikan

Oct 31, 1868

He was an American physicist. Made ans experiment measuring the force on tiny charged droplets of oil suspending against gravity between two metal electrons.

Ernest Rutherford

Oct 28, 1871

He discovered that uraniom emits fast moving particles that have a positive charge. He aimed a narrow beam of alpha particles at the gold and then observed the flash, could figure the path of an alpha particle after it passed through the gold. he died in 1937

Bohr

Oct 30, 1885

Agreed with Rutherford's model of a nucleus surrounded by a large volume of space. In his model the electrons move in spherical orbits at fixed distances from the necleus. Bohr died in 1962.

Ernest Marsden

Oct 31, 1889

He was asked to find out what happens to alpha particles when they pass through a thin sheet of gold. He died in 1970.

James Chadwick

Oct 31, 1891

Confirms the existance of nevtrons which have no charge. Atomic nucleuscontain neutrons and positiveley charged protons. He died in 1974.

Hantaro Nagaoka

Oct 30, 1904

Suggested that an atom has a central nucleus. Elestrons move in orbits like the rings around Saturn.

Louis de Broglie

Oct 30, 1924

Propses that moving particles like electrons have some properties of waves. Collected evidence to support that.

Erwin Schrodinger

Oct 31, 1926

Develops mathmatical equations to describe the motion of electrons in atoms. He developed the Electron Cloud Model.