As we look at the world around us, we seem to see certain regularities in how the world operates. For example, if I drop a ball there is a pattern in the way it falls back to the earth, it behaves in a similar manner every time. This has led to the speculation that there are basic rules that determine how the world around us behaves. Scientists try to find these rules that govern the natural world. They do this using the processes of
We observe certain regularities and make a hypothesis or form a theory, i.e. try to guess what the rules are, and then test our hypothesis or theory by experimentation. When we make hypotheses, we prefer hypotheses that are testable. Scientists like hypotheses that make predictions that can be tested and shown to be either correct or incorrect.
Note that although a prediction may be correct, that does not prove the hypothesis is correct, merely that it is not incorrect in that particular case. We cannot prove a hypothesis is correct, only that it is consistent with our observations and the tests we have been able to make. However, if a hypothesis is consistent with a wide range of observations and experiments, we begin to have confidence in it and even call it a law, e.g. Newton's Laws of Motion. Calling it a law does not necessarily mean it is correct and immutable. (Ironically, Newton's Laws of Motion are known to be wrong. They are approximately correct in many cases, but are not applicable in all situations.) Our theories often have to be modified as we acquire new information.
Another important characteristic of science is that scientists should have a little skepticism. When someone proposes a theory, other scientists have the task of testing it. They look for problems or shortcomings in the theory to see if it is accurate, and a little skepticism aids in this process. Typically, it is only after a period of testing that a theory is generally accepted as a good rule or explanation, and even then only until it fails a test and a better theory is developed.