Some Notable Greek Scientists

Pythagoras (6th century BC)
Realized the earth was a sphere and established the numeral basis of musical harmonics.

Empedocles (c. 490-430 BC)
Held that all matter consisted of four elements.

Democritus (c.460-370 BC) and Leucippus (5th century BC)
Suggested that matter was made up of extremely small, identical, invisible particles called atoms.

Hippocrates (c.460-c.377 BC)
Became known as ‘the father of medicine’.

Euclid (fl.c.300 BC)
Set out the principles of geometry.

Aristarchos of Samos (c.310-230 BC)
Realized that the earth rotates about its own axis and orbits the Sun.

Archimedes (c.287-c.212 BC)
Pioneered the field of mechanics and invented many ingenious devices.

Eratosthenes of Cyrene (c.276-c.194 BC)
Calculated the circumference of the Earth with a creditable degree of accuracy.

Source: World History, 50 key milestones by Ian Crofton
Source: Wikipediajaneedit