Conversation so far:
who found out that the simplest form of matter is the atom
Democritus was a Greek philosopher who was the first person to use the term atom.
did john dalton find out that the simplest form of matter is the atom
John Dalton was the first to adapt Democritus’ theory into the first modern atomic model.
when did dalton propose the first modern atomic model
Experiments with gases that first became possible at the turn of the nineteenth century led John Dalton in 1803 to propose a modern theory of the atom.

Question: is the theory accurate
Self-contained rewrite: is john dalton's atomic theory accurate