The Scientific Method
The scientific method is a process implemented in experimentation that is used to answer questions surrounding an observation. However, this is a loose definition as scientists often will modify this process when direct experimentation is not available. For example, scientists studying climate change over large time periods cannot fast-forward time to observe how the climate fluctuates; a modified scientific method must be devised. Even when modified, the overall goal remains the same. That is, to discover cause and effect relationships by asking questions about an interesting observation, gathering evidence, and then collating all available information in hopes of reaching a logical conclusion.
Basic Steps
The scientific method can be broken down into five basic steps with one additional step for feedback and communication:
Make an observation.
Ask a question.
Form a hypothesis, or a testable explanation.
Make a prediction based on the hypothesis
Test the prediction
Use the results to formulate a new hypothesis, prediction, etc. (i.e., iterate) and communicate the results.
The scientific method is shown here as a series of steps, however, new information or a change in perspective might cause a scientist to reconsider how they're approaching their experiment. In the process, their use of the scientific method may not be exactly as presented here; for example, there may be backtracking and repeating of steps throughout the course of the experiment. This is the logic behind point six; science is a process that will most likely undergo iterations throughout the course of a scientific inquiry.
Details
Now that you are familiar with the basics of the scientific method, let's discuss each step in a bit more detail.
1) Make an Observation: The scientific method begins when you make an observation. This observation can really be anything, but the key is that you are intrigued by it and want to know more.
2) Ask a Question: Now that you've made the observation and are interested in knowing more, it is now time to formulate your questions. How, what, when, where, why, or who? You will most likely generate a long list of questions, but it is important to then review your list to select those which you believe to be the most prominent and worthy of trying to answer.
Further, at this point, it is important to do background research on your observation. Perhaps someone has already made the same observation(s) as you and has already answered your question(s). You want to be efficient here and not find yourself repeating work that has already been done. The goal is to craft new questions in an effort to discover an answer that has never been observed before.
3) Form a Hypothesis: A hypothesis is an educated* guess about how something might work. It is an attempt to answer the question you have crafted about the observation. Also, it is important that your hypothesis is able to be tested.
4) Make a Prediction: A prediction is an outcome that we would expect if the hypothesis is correct. In other words, if we have crafted an educated guess that is true, we would then expect to see a particular result demonstrated by the experiment.
5) Test the Prediction: Now, to test the hypothesis, we need to perform an experiment associated with that particular prediction. It is important to maintain rigor while conducting your experiment so as to ensure the veracity of the results. This is generally done by changing only one factor at a time while keeping all other conditions the same. Last, it is important to repeat the experiment a few times to ensure that the results your are observing are actually true and not some sort of anomaly.
6) Iterate and Communicate the Results: Review the results of your experiment to see if they support your hypothesis or not. Furthermore, it is important to communicate your results to others. Professional scientists do this by publishing their findings in a scientific journal and presenting via either a presentation or poster at a scientific conference.
*Note, here, "educated" means that the hypothesis must be consistent with known facts as well as testable and falsifiable. If the hypothesis fails to meet these criterion, it should be replaced with a hypothesis that does.
Often times, scientists find that their predictions were not correct and that their hypothesis was not supported by the evidence. When this is the case, the results are still communicated as the information is valuable to science, but then a new hypothesis along with a new prediction will be formulated based on the information gained from the experiment. This is the iterative process of the scientific method as a number of steps from the method are repeated. Last, even if the hypothesis was validated by the experiment the first time around, the scientists may want to again test the hypothesis, but this time, in a new way.
Example
Observation: My computer won't turn on!
Question: Why won't my computer turn on?!
Hypothesis: Again, a hypothesis is an educated guess, which is also testable, that attempts to answer the question you are posing. In this case, we are going to start with the hypothesis that the computer won't turn on because it is not plugged in.
Prediction: Once more, a prediction is an outcome that we would expect to see if our hypothesis is correct. Here, if our hypothesis is correct, then, when we would expect the computer to be unplugged and, once plugged in, the computer should turn on.
Results: At this point, we perform our experiment, which is to check to see if the computer is unplugged. There are two likely outcomes:
The computer is unplugged. Then, once the computer is plugged in, the computer turns on. In this instance, the hypothesis is supported and likely correct.
The computer is already plugged in and the hypothesis is not supported, which indicates that it is likely wrong.
The results of an experiment can either support or oppose a hypothesis. It is important to note that a hypothesis can't conclusively prove that it's correct, but it does mean that there's a high probability of its correctness. Conversely, if the results contradict the hypothesis, it is very likely that it is not correct and should be rejected. However, a possibility that should always be considered is that there may have been a flaw within the experiment, which produced a specious result. In general, scientists are incredibly meticulous with their work to minimize such a possibility, but it is still possible.
Now, After checking to see if the computer is unplugged, we notice that it is actually already plugged in.
Iterate: At this point, we must reflect on the results and use them to guide us forward. Since we were forced to reject our initial hypothesis, we must make a new one and repeat the method once more.
Hypothesis: The hard drive is broken and is causing the computer to not turn on.
Prediction: Here, we would expect to see the computer turn on once the hard drive is replaced and plugged in.
Results: Performing another experiment, we replace the hard drive, plug the computer in, and hit the power button. Once more, there are two likely outcomes:
The computer turns on and our hypothesis is likely correct.
The computer still won't turn on indicating that our hypothesis is most likely incorrect.
Success! We observe that the computer has finally decided to turn itself on, which means that we can accept our new hypothesis and finally finish that last minute paper on wireless charging for our physics class.
Iterate: Since we have accepted our new hypothesis, we don't need to worry about formulating a new one. However, we might decide to conduct additional tests to further confirm our hypothesis, or revise it to be more specific. For example, we might decide to go on an investigate why it was that our hard drive broke in the first place.
As is often the case with most scientific investigations, the iterative nature of the scientific method has been demonstrated here. In other words, science is often performed in a cycle rather than a straight line. The results observed at the conclusion of one experiment becomes feedback for new and improved questions, which leads to hypothesis formulation all in the hopes of learning something new about the world around us.
Conclusion
Whether it's physics, geology, psychology, or any other scientific discipline, the scientific method is the ethos that all scientists must follow to ensure the highest probability of producing accurate results. In other words, a strict adherence to this methodology ensures that the answers are logical and supported by evidence. That said, the system isn't perfect and wrong conclusions are sometimes reached. Thankfully, there are many checks and balances implemented by scientists to ensure that their results are credible. Further, before the communication portion of the method, scientists will share their work with other experts in their field who critically analyze the experiment for its integrity. After all of the hurdles are cleared, only then are the results shared with the world and humanity's tree of knowledge grows a bit more.