pdf for atomic theory

1. Early Atomic
tHEORY
Ancient Greeks

2. Empedocles (490-430 BCE)
Empedocles was a Greek philosopher who is best known for his belief
that all matter was composed of four elements: fire, air, water, and
earth.

3. The Four Elements.

4. Atomic theory was invented by the ancient Greek
philosophers Leucippus and Democritus, who speculated that
the world essentially consists of myriads of tiny indivisible
particles, which they called atoms, from the Greek atomon,
meaning uncuttable.
Democritus and Leucippus (460-
370 BCE)

5. Aristotle (384-322 BCE)
Aristotle is a one of the most influential Greek
philosopher that rejected the atomism of Democritus.
Aristotle assumed that only observable things could be
proven true.

6. Aristotle did not believe in the atomic
theory and he taught so otherwise. He
thought that all materials on Earth were not
made of atoms, but of the four elements,
Earth, Fire, Water, and Air. He believed all
substances were made of small amounts of
these four elements of matter.

7. hot + dry = FIRE
hot + wet = AIR
cold + dry = EARTH
COLD + WET = water
Hot , Dry , Wet , Cold

8. Epicurus (350-275 BCE)
Epicurus believes that the basic constituents of the world
are atoms (which are uncuttable, microscopic bits of
matter) moving in the void (which is simply empty space).
Ordinary objects are conglomerations of atoms.

9. Lucretius (100-51 BCE)
Lucretius was an atomist and a materialist who
believed that nature consisted of two
fundamental principles, the atom and the void.
He also argued against supernatural causes of
phenomena in favor of natural ones.