1. Democritus, Aristotle, and Other Greeks Ben Crouch

2. 450 BC  Empedocles (490-430) proposes a theory that all matter is made up of four basic elements: earth, air, fire, and water. His theories are accepted in Europe until the 17th century. Gascoigne, Bamber. “History of Chemistry” HistoryWorld. From 2001, ongoing. http://www.historyworld.net/wrldhis/PlainTextHistories.asp?groupid=2458&HistoryID =ac20&gtrack=pthc

3. 420 BC  Democritus (460-370) states that all matter is made of tiny, invincible, inseparable particles that cling together to make different substances. He calls them atoms, from the Greek atomos, which means “indivisible”. This theory is the basis for modern atomic theory. "Democritus." The-History-of-the-Atom -. Web. 24 Nov. 2014..

4. 340 BC  Aristotle (384-322) combines Empedocles and Democritus’ theories into a single atomic theory. He believed atoms were either hot or cold and either wet or dry. These properties determined which of the four basic elements the atom was. "Aristotle's Contribution." Atomic Model History. 27 Nov. 2010. Web. 24 Nov. 2014..

5. 3 rd Century BC  Democritus, Epicurus, and Lucretius found the school of thought known as Atomism. This philosophy states that all matter in the universe is made of atoms. Everything that is not an atom is a void. "Atomism." The Free Dictionary. Farlex. Web. 26 Nov. 2014..

6. 3 rd Century BC  Greek science is practiced in Alexandria. Many of the tools used in modern chemistry are also used and invented here. Great advancements are made in the field of chemistry. Alchemy begins. "24.1 The Science of Alexandria¶." 24.1 The Science of Alexandria — The Outline of History by H. G. Wells. Web. 26 Nov. 2014..