The first step in using the scientific method is to have an idea and then make observations. By observation, you can gain an intuition as to whether your idea may have credence. One famous example is Isaac Newton. By observation from ideas, he developed three laws concerning motion: inertia, acceleration and opposing forces.
Once ideas and observations have been made that suggest that the idea may be plausible, a scientist will develop a hypothesis. A hypothesis will make a statement that can be tested. There are two possible outcomes -- null, which means that there was no effect, and positive, which means that the effect occurred. In scientific words, the latter means that the null hypothesis is rejected. In this case, the theory is repeated again and again under the most rigorous circumstances.
If the results of repeated testing consistently reject the null hypothesis, the principle or idea in which it's based becomes a scientific theory. One example is of Albert Einstein. He developed, tested and proved his theory of relativity. One part of this scientific theory showed that large proportions of energy could be released from smaller proportions of matter. It is famously expressed in the equation e = mc2. This principle underpins nuclear physics.
One of countless examples of the association between science and engineering is the electromagnetic telegraph. This, notes Daniel P. McVeigh in an article published by Columbia University, was invented in the United States in 1831 by Joseph Henry. It should be stated that there are many claimants to being the original inventor of the telegraph. However, through observation and the development of an idea through hypothesis testing, Henry first sent an electric charge along 5,000 feet of wire. He subsequently showed that the underlying scientific concept worked over much longer distances.
Samuel Morse not only developed the Morse code but also built, with the financial assistance of Congress, the first telegraph system between Washington DC and Baltimore in 1843. Thus, without the scientific method established by Joseph Henry and others, the telegraph would not have been built. Without the engineers to put the scientific theory to good practical use, it would have remained a theory.