| A | B |
|---|
| revolution | a sudden and great change |
| geocentric | the belief that the Earth is at the center of the universe |
| heliocentric | the belief that the sun is at the center of the universe |
| astronomer | scientist who study the motions of the stars and planets |
| ellipses | oval paths |
| heresey | to go against the official teaching of the Catholic church |
| scientific method | an orderly way of collecting and analyzing data |
| rationalism | the school of thought that says all knowledge is based on reason |
| Principia | a book published by Newton that discussed the law of gravity |
| gravity | the force that pulls objects toward Earth that are at or near its surface |
| theory | an explanation of how or why something happens;it may or may not be true but it seems to fit the facts |
| hypothesis | an explanation of the data;not necessarily true |
| science | any organized study of the natural world and how it works |
