| A | B |
|---|
| Early Greek philosophers (circa 430 B.C.) approach to science was... | theoretical & speculative. |
| Early Greek philosophers (Empedocles, circa 430 B. C.) decided the earth was made of 4 "elements". | earth, air, water, and fire |
| 100 years after the early Greek philosophers, Aristotle (circa 335 B.C.) supposed the heavens were composed of a 5th element - | aether |
| The medieval alchemists got mired in magic and quackery, but they came to shrewder, more reasonable conclusions than the Greeks because they at least | handled the materials they speculated about. |
| By the 17th century, the word alchemist had become changed to | chemist. |
| One of the first new chemists was | Robert Boyle. |
| Robert Boyle (1627-1691) | - the first modern chemist; one of the pioneers of the scientific method; best known for Boyle's Law. |
| Henry Cavendish (1731-1810) discovered "inflammable air" which formed water on combustion, showing that water could not be an element. | His practical chemical work began to make clear which substances could be broken down into simpler substances and which could not. |
| The Cavendish experiment was the first to measure the force of gravity between masses in a laboratory and to produce an accurate value for the earth's... | density. |
| Antoine Lavoisier (1742-1794) resolved the supposed element "air" into oxygen and nitrogen. By now, it had become clear that none of the Greek "elements" was an element by Boyle's criterion. | Lavoisier found and termed both oxygen and hydrogen, helped construct the metric system, put together the first extensive list of elements and helped reform chemical nomenclature. He also was the first to establish that sulfur was an element rather than a compound. |
