jan 1, 1805 - John Dalton proposed his idea of the atom.
Description:
Dalton's theory states that all matter is made up of atoms, and that each element has its different atoms. These experiments lead to the atomic weight of each element, concluding that atoms are objects with mass that can be combined, creating compounds.Added to timeline:
Date:
jan 1, 1805
Now
~ 221 years ago