When carrying out scientific investigations scientists usually form an initial idea to explain their observations. The initial idea is knows as a hypothesis. A hypothesis is tested by making further observations and seeing if they match the observations that would be expected. Scientific testing is usually based on two questions:
- If the hypothesis is correct, what would we expect to see?
- Does what we actually observe match this?
Hypothesises are supported when actual observations match the expected observations. Hypothesises are contradicted when they do not match. When the results do not support the hypothesis, further investigation is necessary. This would be a new hypothesis to test.
If it is not possible to make any observations relevant to the hypothesis, it is not testable and cannot be developed into a theory. When a hypothesis is continually supported by scientific evidence it may become accepted as a theory.