Who: John Dalton
What: Proposed that “matter is composed of extremely small particles called atoms, atoms are indivisible and indestructible, atoms of a given element are identical in size, mass and chemical properties, atoms of a specific element are different from those of another element, different atoms combine in simple whole-number ratios to form compounds, and in a chemical reaction atoms are separated, combined or rearranged.” When: 1803
Where: Born Eaglesfield, United Kingdom. Conducted his experiments in Manchester, United Kingdom.
Why: Dalton was inspired by Democritus and wanted to improve and experiment scientists previous work.
How: Studied Joseph Prousts work