The Scientific Method
2 Approaches to Studying Science
• “Fishing” expeditions
• The scientific method
“Fishing” Expeditions
• This type of research is not hypothesisdriven in the classic sense.
• It includes designing experiments that are
geared towards harvesting large amounts of
information/data that can be used later to
generate hypotheses.
• These types of experiments include
techniques like pull-downs followed by
MudPIT, microarrays, RNA seq, genome
sequencing, and many others.
• No guarantee you’ll get something useful.
Any even if you do, you might not know
what to do with it. Can be very “hit or miss.”
The Scientific Method
Science is a way of examining and finding order in
the natural world. It is a human construct that is
formed by dynamic processes that seek to expand
our current body of knowledge.
Because all the laws, principles, and theories of
biology result from scientific inquiry, it is worth
looking into how we perform this type of inquiry, and
identifying components necessary for its success.
The Scientific Method
Scientific inquiry, a term I use interchangeably with the
scientific method, is carried out in five stages:
1. Observations lead to the formation of a research question.
2. The question leads to an educated guess, or hypothesis, about the
answer. This can be based on prior research, knowledge, or even
intuition.
3. The hypothesis must be tested in a way that allows it to be proven
false.
4. Results are interpreted.
5. Conclusions about the value of the hypothesis are made based on
interpretation of results. These conclusions are then communicated
to other interested parties.
1. What makes a good research
question?
• Can the question be
answered?
• Can the question be
answered “no”?
• Does the questions
specifically address
the observations?
2. What makes a good hypothesis?
• A hypothesis must be testable.
• Assumptions must be defined; “Normally” has no
reference point and contributes nothing to a
hypothesis.
• A hypothesis should specifically address the
observations you based your research question
on.
• You should always generate a null hypothesis,
or an alternative hypothesis, that addresses the
possibility that the opposite of what you expect
to happen might actually happen.
2. What makes a good hypothesis?
While hypotheses can
be shown to be false,
they CAN NOT be
proven!!!
You can show support
for your theory
(hypothesis), but this
is not proof, but
evidence.
3. Testing the Hypothesis
• First and foremost, you must have a control, or a
standard of comparison. This is an individual or group of
experimental subjects that is not exposed to the
treatment being investigated. It serves as a reference to
compare with experimental groups that are exposed to
your treatment.
• Often the data you seek are obtained by varying one
experimental variable, the independent variable, and
observing and measuring what change this has on the
dependent variable.
• Your results must be repeatable (3x minimum).
The Miller-Urey Experiment: a Case
Study of the Scientific Method
Miller-Urey: The Scientific Method
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What question did they address?
What was their hypothesis?
What would be a good null hypothesis?
What experiment did they use to test their
hypothesis? What was their control?
• What conclusion did they reach after
obtaining the results from this experiment?
Worksheets and Cabbage
experiments
Wednesday there will be a pre-lab
quiz