HISTORY OF ATOMS
The concept of the atom was first put forth 2300 years ago by a Greek named Democritus of Abedra in the 4th Century B.C. He proposed this term as an explanation to the composition of matter. In Greek the term atomos means indivisible.
Democritus was basically implying that if you were to cut matter, for example a piece of wood, into smaller and smaller pieces, that eventually you would reach a point where you could no longer cut it.
However, at the same time Democritus proposed this picture, another Greek philosopher suggested an alternative explanation. Aristotle, one of the most influential people of his time, described all matter as being composed of the "four basic elements" fire, earth, air and water. 3
THE GREAT ATOM DEBATE
Due to the extreme influence Aristotle had at the time, his concept of matter was quickly accepted and Democritus' ideas were laughed at by the other Greek's.
The fact that Aristotle's ideas were so widely accepted, set the progress of science back thousands of years! Way to go Aristotle!
EXAMPLE OF ARISTOTLE'S ARGUEMENT:
Consider a piece of wood. When I burn it I release the fire inside of it and some of it turns to air (smoke). The wood then turns to dust which goes back into the earth. Thus wood is composed of fire, earth and air!
The important take away point is that Aristotle's ideas were accepted because he could "prove" them by completing a sort of experiment. Whereas Democritus' idea of an indivisible atom could not be proved, thus it was quickly rejected.