The scientific method is a refined version of a technique called induction. Induction is a technique where you generalize from a series of effects or observations to produce laws or rules. Deduction is the opposite, you would start from a rule to deduce an effect. The ancient Greeks discussed induction widely, and this discussion was continued by Arab Alchemists and many medieval European philosophers. The scientific method refines the process of induction so that it could more consistently produce valuable new knowledge. This page only briefly summarizes the scientific method.
The scientific method taught in second level (high) schools around the world is key to all science. Even so, it is important to realize that there is a lot more to the workings of science including social and creative factors. The textbook description of the scientific method might read as below:
If the experiments properly agree with the expectations then the hypothesis becomes a theory and is considered proven. If the results of all the experiments do not agree with the expected results then the hypothesis is rejected or modified and retested.
Sometimes it is not just the original hypothesis that is subject to experimental testing but also any necessary consequences. In the 15th, 16th and 17th century, the hypothesis that the earth revolved around the sun was proposed. But there was a necessary consequence of that hypothesis; if the earth revolved around the sun then that meant that stellar parallax should be observed. Parallax implies that there should be changes in the position of stars in a night sky if the earth was moving (see Stellar Parallax). Although there was already considerable support for the hypothesis that the earth revolved around the sun in the 1600's, the inability to observe parallax provided a problem for the hypothesis. Today, you will find reputable astrophysicists and philosophers of science who believe the theory that the earth revolved around the sun was not really proven until the 18th century at the earliest and the 19th century at the latest when stellar parallax was finally observed. Galileo's proofs were not considered sufficient by many because they could not account for stellar parallax.