jan 1, 460 BC - Democritus - The beginning
Democritus was a Greek philosopher whose life details are not based on solid facts. People agree he was born around 460BC in Abdera, Greece. Democritus kickstarted the atomic theory in his beliefs that all matter must be made of an identical minuscule particle. Historians say that his visions of atoms were 'eternal and indivisible; absolutely small, so small that their size cannot be diminished.' However, his vision of an atom was a uniform sphere and left many questions that wouldn't be answered for more than 2000 years.
Added to timeline:
Atomic Model Timeline