1800-1875GS

This picture comes from: [] Name: John Dalton DOB-DOD September 6, 1766- July 27th 1844 Country of Origin: Cumberland, England

Dalton was a British chemist and physicist, born in Cumberland, England. He  provided the beginnings of the development of a scientific atomic theory, thus facilitating the development of chemistry as a separate science. His contributions to physics, particularly to meteorology, were also significant.

1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a of atoms.

This picture comes from: [] Name: Sir William Crookes DOB-DOD June 17th 1832-April 4th 1919 Country of Origin: London, England Sir William Crookes, was a chemist and physicist who attened the Royal College of Chemistry in London, and worked on spectroscopy. He was a pioneer of Vacuum Tubes, inventing the Crookes Tube. Crookes also discovered the formerly unknown element of Thallium. He also identified the first known sample of Helium. One of the most important discoveries of his was uncovering the properties of Cathode Rays, showing they travel in a straight line. With his Crookes Tube, William Crookes discovered the properties of a Cathode Ray, which helped J.J Thomson to discover the electron. This advanced the scientifc world greatly.