SCIENTIFIC METHOD STEPS
CSc21 Fall 2014
As more proof that there is no one way to "do" science, different sources describe the steps of the
scientific method in different ways. Some list three steps, some four and some five.
Fundamentally, however, they incorporate the same concepts and principles.
Image courtesy William Harris
For our purposes, we're going to say that there are five key steps in the method.
Step 1: Make an observation
Almost all scientific inquiry begins with an observation that piques curiosity or raises a question.
For example, when Charles Darwin (1809-1882) visited the Galápagos Islands (located in the
Pacific Ocean, 950 kilometers west of Ecuador), he observed several species of finches, each
uniquely adapted to a very specific habitat. In particular, the beaks of the finches were quite
variable and seemed to play important roles in how the birds obtained food. These birds
captivated Darwin. He wanted to understand the forces that allowed so many different varieties
of finch to coexist successfully in such a small geographic area. His observations caused him to
wonder, and his wonderment led him to ask a question that could be tested.
Step 2: Ask a question
The purpose of the question is to narrow the focus of the inquiry, to identify the problem in
specific terms. The question Darwin might have asked after seeing so many different finches was
something like this: What caused the diversification of finches on the Galapagos Islands?
Here are some other scientific questions:
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What causes the roots of a plant to grow downward and the stem to grow upward?
What brand of mouthwash kills the most germs?
Which car body shape reduces air resistance most effectively?
What causes coral bleaching?
Does green tea reduce the effects of oxidation?
What type of building material absorbs the most sound?
Coming up with scientific questions isn't difficult and doesn't require training as a scientist. If
you've ever been curious about something, if you've ever wanted to know what caused something
to happen, then you've probably already asked a question that could launch a scientific
investigation.
Step 3: Formulate a hypothesis
The great thing about a question is that it yearns for an answer, and the next step in the scientific
method is to suggest a possible answer in the form of a hypothesis. A hypothesis is often defined
as an educated guess because it is almost always informed by what you already know about a
topic. For example, if you wanted to study the air-resistance problem stated above, you might
already have an intuitive sense that a car shaped like a bird would reduce air resistance more
effectively than a car shaped like a box. You could use that intuition to help formulate your
hypothesis.
Generally, a hypothesis is stated as an "if … then" statement. In making such a statement,
scientists engage in deductive reasoning, which is the opposite of inductive reasoning.
Deduction requires movement in logic from the general to the specific. Here's an example: If a
car's body profile is related to the amount of air resistance it produces (general statement), then a
car designed like the body of a bird will be more aerodynamic and reduce air resistance more
than a car designed like a box (specific statement).
Notice that there are two important qualities about a hypothesis expressed as an "if … then"
statement. First, it is testable; an experiment could be set up to test the validity of the statement.
Second, it is falsifiable; an experiment could be devised that might reveal that such an idea is not
true. If these two qualities are not met, then the question being asked cannot be addressed using
the scientific method.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method6.htm
HOW TO USE THE SCIENTIFIC METHOD
The scientific method is the backbone of all rigorous scientific inquiry. A set of techniques and
principles designed to advance scientific inquiry and further the accumulation of knowledge, the
scientific method has been gradually developed and honed by everyone from the philosophers of
ancient Greece to the scientists of today. While there are some variations on the method and
disagreement over how it should be used, the basic steps are easy to understand and invaluable
not only to scientific research but also to solving everyday problems.
Steps
1. Observe. It is curiosity that breeds new knowledge. The process of observation,
sometimes called "defining the question," is simple. You observe something that you
can't readily explain with your existing knowledge, or you observe some phenomenon
that is explained by existing knowledge but which may have another explanation. The
question, then, is how do you explain that phenomenon--what causes it to occur?
2. Research the existing knowledge about the question. Suppose you observe that your car
won't start. Your question is, why won't it start? You may have some knowledge about
cars, so you'll tap into that to try to figure it out. You may also consult your owner's
manual or look online for information about the problem. If you were a scientist trying to
figure out some strange phenomenon, you could consult scientific journals, which publish
research that other scientists have already done. You'd want to read as much about your
question as possible, because the question may have already been answered, or you may
find information that will help you form your hypothesis.
Use the Scientific Method
3. Form your hypothesis. A hypothesis is a possible explanation for the phenomenon you
observed. It is more than a guess, though, because it is based upon a thorough review of
the existing knowledge of the subject. It's basically an educated guess. The hypothesis
should posit a cause-effect relationship. For example, "My car won't start because I am
out of gas." It should suggest one possible cause for the effect, and it should be
something that you can test and which you can use to make predictions. You can put gas
in your car to test the "out of gas" hypothesis, and you can predict that if the hypothesis is
correct, the car will start once you add gas. Stating the effect like a fact is more like a real
hypothesis. For those who are still stuck, use the "if" and "then" statement: If I try to start
my car and it doesn't, then it is out of gas.
4. Test your hypothesis. Design an experiment that will either confirm or fail to confirm
the hypothesis. The experiment should be designed to try to isolate the phenomenon and
the proposed cause. In other words, it should be "controlled." Going back to our simple
car question, we can test our hypothesis by putting gas in the car, but if we put gas in the
car and change the fuel filter, we can't know for sure whether the lack of gas or the filter
was the problem. For complex questions, there may be hundreds or thousands of potential
causes, and it can be difficult or impossible to isolate them in any single experiment.
Keep impeccable records. Experiments must be reproducible. That is, other people must
be able to set up a test in the same way that you did and get the same result. It's
important, therefore, to keep accurate records of everything you do in your test, and it's
essential that you keep all your data. Today there are archives set up which store the raw
data gathered in the process of scientific research. If other scientists need to find out
about your experiment they can consult these archives or ask you for your data. It's
critical that you be able to provide all the details.
5. Analyze your results and draw conclusions. Hypothesis testing is simply a way to
collect data that will help you either confirm or fail to confirm your hypothesis. If your
car starts when you add gas, your analysis is pretty simple--your hypothesis was
confirmed. In more complicated tests, however, you may not be able to figure out
whether your hypothesis is confirmed without first spending considerable time looking at
the data you gathered in your hypothesis testing. Furthermore, whether the data confirms
or fails to confirm the hypothesis, you must always be on the lookout for other things, socalled "lurking" or "exogenous" variables, that may have influenced the results. Suppose
that your car starts when you add gas, but at the same time the weather changed and the
temperature increased from below freezing to well above freezing. Can you be sure the
gas, and not the change in temperature, caused the car to start? You may also find that
your test is inconclusive. Perhaps the car runs for a few seconds when you add gas, but
then dies again.
6. Report your findings. Scientists generally report the results of their research in scientific
journals or in papers at conferences. They report not only the results but also their
methodology and any problems or questions that arose during their hypothesis testing.
Reporting your findings enables others to build upon them.
7. Conduct further research. If the data failed to confirm your initial hypothesis, it's time
to come up with a new hypothesis and test it. The good news is, your first experiment
may have provided you with valuable information to help you form a new hypothesis.
Even if a hypothesis is confirmed, further research is necessary to ensure that the results
are reproducible and not just a one-time coincidence. This research is often performed by
other scientists, but you may also wish to further investigate the phenomenon yourself.
http://www.wikihow.com/Use-the-Scientific-Method