Scientists Timeline

Democritus

460

Greek scholar who is best known for his atomic theory although he was also an excellent geometer. He called the paricles of matter atoms.

John Dalton

Sep 24, 1803

Dalton consolidated his theories in his New System of Chemical Philosply. He proposed an atomic theory with shpherical solid masses in motion.

Atomic theory of matter.

Sep 28, 1803

John Dalton developed the first useful atomic theory of matter around 1803.

JJ Thomson

Sep 24, 1897

He tired to craft mathematical models that would reveal the nature of atoms and electromagnets forces. Described the atom as a ball of positive charge containing a number of electrons.

Canal Rays

Sep 28, 1897

Studied "Canal Rays" and found they were associated with the proton H +

E. Rutherford

Sep 24, 1911

He was awarded the B.A. Research degree and the Coutts Trotter studentship of Trinity college. He also used his "gold foil" experiment to determine that he nucleus of the atom is very dense and had a positve charge. He aslo assumed that the electrons were outside the nucleus of the atom.

Niels Bohr

Sep 25, 1922

He explained that atomic structure of the atom as "successive orbital shells of electrons." His model is known as the Bohr Planetary model.

Schrodinger

Sep 25, 1932

He identified the electron model as the probable location of moving electrons.

James Chadwick

Sep 25, 1932

James discovered particles within the nuclues that has mass.

Neutron discovered

Sep 28, 1932

James Chadwick used Alpha Particles he discovered a neutral atomic particle with a mass close to a proton. Thus discovered the neutron.

Isaac Newton proposed a mechanical universe

Oct 5, 2009

Isaac Newton proposed a mechanical universe with small solid masses in motion.