| − | A scientific theory is exactly what it sounds like, a theory about science. These theories are really the opinions of scientists. Any scientist can create a theory, or opinion, | + | A scientific theory is a scientific hypothesis that has undergone numerous checks that confirm its validity as a theory. |
| − | Scientific theories are regarded as true when enough people are in agreement. For example, you may believe in the theory of gravity since you experience it at all times. Other theories such as global warming or the age of the earth are harder to prove since we cannot truly measure them. Weather records have only been reliably kept for about 20 years. Before that, there were no standard tools to measure temperature. Everyone had a thermometer that measured differently, which is why we have two temperature scales; fahrenheit and celcius.
| + | For a theory to exist, it must start as a hypothesis, go through vigorous testing and re-testing, and remain true throughout the testing. If the hypothesis remains true, then it can be identified as a theory. If it does not, the scientist must return to his hypothesis to alter it or completely start over. |