Historically science began with the ancient Greeks. Here is a complete list of ancient Greek scientists. If anything religion and spirituality have gotten in the way. http://www.ics.forth.gr/~vsiris/ancient_greeks/index.html
Agatharchos. Greek mathematician. Discovered the laws of perspectives.
Anaxagoras of Clazomenae (480-430 B.C.). Greek philosopher. Believed that a large number of seeds make up the properties of materials, that heavenly bodies are made up of the same materials as Earth and that the sun is a large, hot, glowing rock. Discovered that the moon reflected light and formulated the correct theory for the eclipses. Erroneously believed that the Earth was flat.
Links: Anaxagoras of Clazomenae, MIT
Anaximander (610-545 B.C.).Greek astronomer and philosopher, pupil of Thales. Introduced the apeiron(infinity). Formulated a theory of origin and evolution of life, according to which life originated in the sea from the moist element which evaporated from the sun (On Nature). Was the first to model the Earth according to scientific principles. According to him, the Earth was a cylinder with a north-south curvature, suspended freely in space, and the stars where attached to a sphere that rotated around Earth.
Links: Anaximander, Internet Encyclopedia of Philosophy, Anaximander, Encyclopedia Britannica, Anaximander of Miletus, MIT
Anaximenes (570-500 B.C.). Pupil of Anaximander. According to him, the rainbow is a natural phenomenon, rather than the work of a god. Basic principle of the universe is air.
Links: Anaximenes, Internet Encyclopedia of Philosophy, Anaximenes of Miletus, Encyclopedia Britannica
Andronikos of Kyrrhestes (50 B.C.). Built, in Athens, the Tower of Winds, a water clock combined with solar clocks, the most famous time-keeping device of the Greeks.
Antiphontas. Greek mathematician. Used polygon approximations for the circle to find and approximate vale for pi.
Apollonius of Perga (262-190 B.C.). Mathematician that did a significant amount of work on the conics (circle, ellipse, parabola, and hyperbola). His work was summerized in his book Conics. Considered the last great synthetic geometer until the end of the eighteenth century.
Aristarchus of Samos (310-230 B.C.). Proposed that the sun is at the center of the universe with Earth along with the other planets circulating around it. He estimated the distance of the sun from the Earth by observing the angle between the sun and the moon when it is exactly half full.
Aristotle (Stagira, 390-330 B.C.). Considered the father of life sciences. He was the tutor of Alexander the Great. Undertook the classification of animals and plants at a large scale. His main discovery in embryology was that the mother's contribution is as important as the father's. Believed that the Earth was static and at the center of the universe. He also believed, erroneously, that motion was due to the tendency of all objects to reach there natural state. He discovered that free fall is an accelerated form of motion, but also believed that heavier objects fall faster than lighter ones. He considered chemical elements, which cannot be decomposed, to be the constituents of all bodies. He was the founder of the Lyceum in Athens, also called the peripatetic school because the philosophers were thought while walking.
Archimedes (Syracuse, 287-212 B.C.). Greek mathematician and engineer which is included among the top ranking mathematicians in history. Also a natural philosopher. He demonstrated that all numbers can be written down, by writing down the number of grains of sand needed to fill the entire universe. He expertly used the method of exhaustion developed by Eudoxus. He found ratios of the volumes of various figures, such as that of a sphere and a cylinder with a height equal to the diameter of the sphere which is equal to two thirds. He was the first to apply mathematical laws to levers. He is also known for his discovery that a body immersed in fluid displaces an amount of fluid equal to its own mass. Legend has it that he discovered this while in the bath and later ran naked around the streets of Syracuse shouting Eureka (I have found it). He used levers to pull a fully loaded ship on shore, thus supporting his statement: "give me a lever long enough and a place to stand and I can move the Earth". According to legend he was killed by a soldier while contemplating geometric figures drawn in the sand, even though the soldier's commander had ordered Archimedes' life spared.
Links: Chris Rorres' Archimedes Web Page (Drexel University), Archimedes of Syracuse, University of St Andrews, Scotland, Archimedes, Encyclopedia Britannica
Archytas of Tarentum (420-350 B.C.). Greek mathematician. Built a series of toys, among them a mechanical pigeon propelled by a steam jet. Developed the theory for the pulley.
Callippus (Cyzicus, 370-300 B.C.). Greek astronomer, student of Eudoxus. Showed that at least 34 spheres are needed to account for the movement of the moon, planets, and stars.
Conon (Samos, 300-??? B.C.). Greek mathematician.
Democritus (Abdera, Thrace, 470-380 B.C.). Greek philosopher. Expanded the concept of atoms that was introduced by his teacher Leucippus and showed that atoms are the basis of all form of matter. He recognizes that the Milky Way consists of a number of stars and that the moon is similar to Earth.
Links: Democritus, Encyclopedia Britannica, Democritus, Internet Encyclopedia of Philosophy, Democritus of Abdera, University of St Andrews, Scotland
Denostratus. Found a way to square the circle (calculated the ratio of it circumference over its diameter.
Diogenes of Apollonia (600 B.C.) Diogenes was a pupil of Anaximenes, whom he followed in making air the primary element of all things but regarded that there was an intelligent principle behind the order of the Universe. He wrote a number of books on Cosmology.
Diocles (180 B.C.). Investigates properties of the curve he names cissiod (meaning ivy).
Empedocles (Akragas, now Cicily, 492-440 B.C.). Natural philosopher. Introduced the idea of elements. Recognized the heart as the center of a system of blood vessels, but erroneously suggested that the heart is the origin of human emotions. Considered that fire, air, earth, and water as the elementary substances. According to legend, he died by falling into a volcano's crater after failing to become a god as he predicted.
Epicurus of Samos (341-270 B.C.). Founder of a philosophical school where atoms are fundamental parts of the philosophy. Believed that fate was governed by laws of nature and not some mysterious gods.
Eratosthenes of Cyrene (276-200 B.C.).. Greek astronomer and mathematician. Calculated the circumference of the Earth and finds a figure of 46,000 km which is close to the present measured value. Also lays down the first lines of longitude on a map of Earth. He also developed a method for calculating all prime numbers: the sieve of Eratosthenes.
Euclid (300 B.C.). Alexandrian mathematician. Author of Elements, a set of twelve volume that portrayed the geometric thought of the Greeks as it developed in the 6th to 4th century B.C. It includes plane and solid geometry, the theory of incommensurables, and the theory of numbers. Like Plato, he disregarded practicality.
Links: Euclid of Alexandria, University of St Andrews, Scotland, Euclid, Encyclopedia Britannica
Eudemus of Rhodes (340 B.C.). Wrote the History of Mathematics, which is lost however.
Eudoxus of Cnidus (408-360 B.C.). Greek astronomer and mathematician. Belonged to the school of Plato. Developed the theory of proportions and the method of exhaustion.
Gorgias (490-380 B.C.). Greek philosopher. According to his nihilist philosophy, nothing exists. If it did exist we could not know it, and if we new it, we could not tell anyone about it.
Heraklitus (Ephesus, 535-475 B.C.). Considered fire to be the primary form of the real world. According to him, everything is in the process of flux (panta rei).
Heracleides (Heraclea, 390-320 B.C.). Greek astronomer. First to suggest that Venus and Mars may orbit the sun. Also suggested the the Earth rotates around its axis once every 24 hours.
Hipparchus of Nicea (190-120 B.C.) Greek astronomer and mathematician. Developed a system of planetary motion with the Earth at the center. This system was later refined by Ptolemy. Used data from a total eclipse of the sun and parallax to determine correctly the distance and size of the moon. The same data gave values for the distance and size of the sun an order of magnitude smaller than there actual values. Compiled the first tables of cord length, forerunner of trigonometric tables.
Hippasus of Metapontum. Pythagorian philosopher and mathematician. Discovered that some numbers are not commensurable or, in today's terms, not all numbers are rational. Discovered the dodecahedron, a solid whose surface constisted of 12 regular pentagons.
Hippocrates of Cos (460-377 B.C.). Considered as the father of Medicine. He and his followers considered that diseases had a rational explanation and cause, hence could be treated.
Links: Hippocrates, Encyclopedia Britannica
Hippocrates of Chios. Wrote his Elements almost one century before Euclid's.
Hypsicles (180 B.C.). Greek mathematician. It is believed that Hypsicles introduced the 360 degree circle to Greek mathematics.
Inopedes (400 B.C. ?). Greek astronomer. Discovered the obliqueness of the elliptic orbit.
Leucippus of Miletus (490-??? B.C.). Greek philosopher. First to introduce the idea of the atom, an indivisible unit of matter. This idea was later extended by his student, Democretus.
Menaechmus (350 B.C.). Brother of Dinostratus. Wrote about conic sections, showing that they can be used to duplicate the cube.
Meton of Athens (440-??? B.C.). Developed the Meton cycle, a 19-year period in which, as viewed from the Earth, the motions of the Ea