THE SCIENTIFIC METHOD
In general terms, scientists should follow a systematization to get a valid deduction about natural phenomena. This systematization is summarized in the steps of the Scientific Method.
Steps of the Scientific Method
I should say that this explanation is a general description of the scientific method. The procedure does not have to follow exactly the arrangement as described here.
The first step in any investigation is OBSERVATION. Observation consists of setting our attention on a portion of the Universe. Through observation we identify specific realities or events from the cosmos by means of our senses.
Once the observation is executed, the researcher elaborates one or more questions, generally ingenerated by the curiosity of the observer. These questions constitute a PROBLEM. The questions MUST MATCH with the remarked phenomenon and they must adhere to objectivity.
The investigator should always take into account that the questions that begin with a "why" are very difficult - if not impossible - to answer. The objective investigator prefers start with questions like "what", "how", "where", or "when". The question could be also "what is for".
Then, the observer, through INDUCTIVE REASONING, tries to give one or more logical answers to such question. Each answer is a tentative introduction that can serve like a guide for the remainder of the investigation. These preliminary solutions to a question are HYPOTHESES.
HYPOTHESIS is a statement that can be false or true that should be submitted to experimentation to verify its level of trueness or falseness.
After he has enunciated one or more hypothesis or proposed explanations, the researcher elaborates one or more PREDICTIONS, which must to be consistent with the observations and hypotheses. To do this, the researcher uses the DEDUCTIVE REASONING.
Each hypothesis should be submitted to an exhaustive test called EXPERIMENTATION. The results of experimentation will determine the final character (false or true) of the hypothesis.
The experimentation can be performed in diverse ways, but the controlled experimentation is a characteristic of the scientific method, of such way that other simpler systems are not viable for the purpose of science.
In controlled experimentation we should have two groups to test: a group called control group or witness group, and other called experimental group.
Both, the control group and the experimental group, are submitted to the same conditions, excluding the variable that has been chosen for the study. The control group is not submitted to the change, but the experimental group is submitted.
The results are observed and the differences between both groups are registered.
If the investigator notes a difference between both groups, then an answer can be deduced.
As the investigation advances, the false hypotheses are rejected one to one, until the plausible verification of the hypotheses that were presented intially.
When a hypothesis is proved as true, scientists process a final statement, which in science is called a THEORY.
Theory is a partially or totally true statement, proved by means of experimentation or natural and observable evidences, only for one time and one place.
If that theory is verified like true for all times and places, then it would be considered a LAW.
A theory is subject to changes, a law is permanent and immutable. A law is comprobable at any time and place of the Cosmos. However, a theory is truth only for a certain place and a given time.
But, we should make clear that there are differences between the meanings of theorem, hypothesis, theory and law in sciences.
A scientific THEOREM is an idea or a proposition that has been considered as true and that must be demonstrable. In mathematics, a theorem is a proposition that has been proved or can be confirmed by means of unequivocal assumptions. For example, the theory of the Inflationary Universe, which when released for the first time, it was presented like mathematical models. Now, the modern observations of real phenomena in the Universe have confirmed it and it has been developed like a theory.
A scientific HYPOTHESIS is a provisional solution for a question generated through the observation of an event. The hypothesis could be false or true, by this, every hypothesis must be tested through experimentation. For example, all reports on the origin of AIDS are hypotheses.
On the other hand, a scientific THEORY is a statement that must contain a setting of real evidence. A theory would be right only if it has been submitted to a rigorous testing, and it only will be true if it is in concordance with facts. A theory could be reworked, as new evidence be accumulated, but the background of truth of the theory will never be altered. Scientific theories are true only for a given time and space. It could not be true for other spots in the Universe. Evolution is a good example of a scientific theory.
A scientific LAW is a statement that is true and valid for all times and all places in the known Universe. A law is true and valid everywhere, for all times. For example, the Laws of Thermodynamics, Laws of Gravity and Axiom of Biogenesis are good examples of scientific laws. The last is one of three Biological Laws. Other Biological Laws are the Intransference of Life and the Irreversibility of Life.
I have seen a semantic problem in many non-scientific dissertations. It refers to a generalized mistreatment of the term "theory". Perhaps the confusion is attributable to the popular idea that the term "theory" applies to all non-verified perceptions, be scientific or not.
There is a major difference between hypothesis and theory. For the scientists, a theory is a true statement applicable for one time and one place because it is based on facts and it has been confirmed by experimentation. For example, the Cell theory, which says that all living beings are constituted by cells. Biogenesis is a theory because it applies only for the known living beings on Earth (a specific place) and it applies only for this time (a specific time). If Biogenesis were observed in other worlds and all times, then we would say the "Law of Biogenesis".