The experimental scientific method is a set of techniques that are used to investigate phenomena, acquire new knowledge or correct and integrate previous knowledge.
It is used in scientific research and is based on systematic observation, taking measurements, experimenting, formulating tests and modifying hypotheses. This general method is carried out not only in biology, but also in chemistry, physics, geology and other sciences.
Through the experimental scientific method, scientists try to predict and perhaps control future events based on present and past knowledge.
Also called the inductive method, it is the most used within science by researchers, this being part of the scientific methodology.
It is characterized by the fact that researchers can deliberately control the variables to delimit the relationships between them.
These variables can be dependent or independent, being fundamental to collect the data that is extracted from an experimental group, as well as their behavior. This allows to decompose the conscious processes into their elements, discover their possible connections and determine the laws of those connections.
The ability to make accurate predictions depends on the seven steps of the experimental scientific method.
Steps of the experimental scientific method
Step 1- Observations
These observations should be objective, not subjective. In other words, the observations must be able to be verified by other scientists. Subjective observations, based on personal beliefs and beliefs, are not part of the field of science.
- – Objective statement: in this room, the temperature is at 20 ° C.
- – Subjective statement: it’s great to be in this room.
The first step in the experimental scientific method is to make objective observations. These observations are based on specific facts that have already occurred and that others can verify as true or false.
Step 2- Hypothesis
Observations tell us about the past or the present. As scientists, we want to be able to predict future events. Therefore, we must use our ability to reason. Scientists use their knowledge of past events to develop a general principle or explanation to help predict future events.
The general principle is called hypothesis. The type of reasoning involved is called inductive reasoning (derivation of a generalization from specific details).
A hypothesis must have the following characteristics:
- – It must be a general principle that is maintained through space and time.
- – It must be a tentative idea.
- – You must agree with the available observations.
- – It must be as simple as possible.
- – It must be verifiable and potentially false. In other words, there must be a way to prove that the hypothesis is false, a way to disprove the hypothesis.
For example: “Some mammals have two hind limbs” would be a useless hypothesis. There is no observation that does not fit this hypothesis! On the contrary, “All mammals have two hind limbs” is a good hypothesis.
When we find whales, which do not have hind limbs, we would have shown that our hypothesis is false, we have falsified the hypothesis.
When a hypothesis implies a cause and effect relationship, we declare our hypothesis to indicate that there is no effect. A hypothesis, which does not affect any effect, is called a null hypothesis. For example, the drug Celebra does not help relieve rheumatoid arthritis.
Step 3- Prediction
From the elaboration of the hypothesis that is tentative and may or may not be true, we must make a prediction about our research and the hypothesis.
The hypothesis should be broad and should be applied uniformly across time and space. Scientists generally can not verify all possible situations in which a hypothesis can be applied. For example, consider the hypothesis: all plant cells have a nucleus.
We can not examine all the living plants and all the plants that have lived to see if this hypothesis is false. Instead, we generate a prediction using deductive reasoning (Generating a specific expectation of a generalization).
From our hypothesis, we can make the following prediction: if I examine the cells of a grass blade, each one will have a nucleus. Now, consider the hypothesis of the drug: the drug (pill) Celebra does not help to relieve rheumatoid arthritis.
To test this hypothesis, we would have to choose a specific set of conditions and then predict what would happen under those conditions if the hypothesis were true.
The conditions you may want to try are the doses administered, the duration of the medication, the ages of the patients and the number of people who will be examined.
All these conditions that are subject to change are called variables. To measure the effect of Celebra (pill for rheumatoid), we need to perform a controlled experiment.
The experimental group is subject to the variable we want to test and the control group is not exposed to that variable.
In a controlled experiment, the only variable that must be different between the two groups is the variable that we want to test.
Let’s make a prediction based on observations of the effect of Celebra in the laboratory. The prediction is this: patients with rheumatoid arthritis who take Celebra and patients who take a placebo (a starch tablet instead of a medication) do not differ in the severity of rheumatoid arthritis.
Step 4- Experiment
We turn again to our sensory perception to gather information. We designed an experiment based on our prediction. Our experiment could be as follows: 1000 patients between the ages of 50 and 70 will be randomly assigned to one of two groups of 500.
The experimental group will take Celebra four times a day and the control group will take a starch placebo four times a day. Patients will not know if their tablets are Celebra or placebo. The patients will take the medication for two months. After two months, medical tests will be performed to determine if the flexibility of the arms and fingers has changed.
Step 5- Analysis
Our experiment produced the following results: 350 of the 500 people who took Celebra reported decreased arthritis at the end of the period. 65 of the 500 people who took the placebo reported improvement.
The data seems to show that there was a significant effect on Celebra. We need to do a statistical analysis to show the effect. Such analysis reveals that there is a statistically significant effect of the Celebra effect.
Step 6. Conclusion
From our analysis of the experiment, we have two possible outcomes: the results coincide with the prediction or disagree with the prediction.
In our case, we can reject our prediction that the Celebra has no effect. Because the prediction is incorrect, we must also reject the hypothesis on which it was based.
Our task now is to reconsider that the hypothesis is a form that is consistent with the information available. Our hypothesis could now be: the administration of Celebrex reduces rheumatoid arthritis compared to the administration of a placebo.
With the current information, we accept our hypothesis as true. Have we shown that it is true? Absolutely not! There are always other explanations that can explain the results.
It is possible that more than 500 patients who took Celebra improve anyway. It is possible that more patients who took Celebra also ate bananas every day and that bananas improved arthritis. You can suggest innumerable other explanations.
How can we prove that our new hypothesis is true? We will never be able The scientific method does not allow to prove any hypothesis.
The hypotheses can be rejected, in which case this hypothesis is taken as false. All we can say about a hypothesis that resists is that we do not find evidence to refute it.
There is a lot of difference between not being able to refute and prove. Be sure to understand this distinction as it is the basis of the experimental scientific method. So, what would we do with our previous hypothesis?
Currently we accept it as true, but to be rigorous, we must present the hypothesis to more tests that may be erroneous.
For example, we could repeat the experiment but change the control and experimental group. If the hypothesis still stands after our efforts to knock it down, we can feel more secure in accepting it as true.
However, we can never say that the hypothesis is true. On the contrary, we accept it as true because the hypothesis withstood several experiments to prove that it was false.
Step 7- Results
Scientists publish their findings in scientific journals and books, in conversations at national and international meetings and in seminars at colleges and universities.
The dissemination of the results is an essential part of the experimental scientific method.
It allows other people to verify their results, develop new tests of their hypothesis or apply the knowledge they have acquired to solve other problems.