Question

how are john dalton scientist

Answer 1

Heya mate!
John Dalton was an English chemist, physicist and meteorologist. He introduced the atomic theory which is also known as Dalton's atomic theory. He has also done a research in colour blindness.
Hope it helps!

Answer 2

John Dalton was born in 1766 at Cumberland in  England. His  father  was a poor weaver. John, after his schooling, began teaching at the age of 12. He became school principal at 18. Later, he taught in college at Glasgow, Edinburgh, London and Manchester. His atomic theory is recognised even today as one of the most brilliant work in the field of science. Dalton, for the first time, suggested a shorthand method for denoting both elements  and  compounds.