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Scientific method is a specific way of "doing science". As described in a number of textbooks, this involves a progression of steps employing both inductive and deductive reasoning, as follows:
The most important learning step which occurs is when observed results
are compared to those predicted, and any discrepancies which are found
need to be explained. It is then that the experimenter realizes that there
must have been certain variables which were not controlled, and which influenced
the outcome in an unexpected manner This then results in a better designed
experiment (see below). The inherent variability in the biological sciences
cannot be over-emphasized, and is something of which you must always be
Whenever you perform an experiment in a practical class, you will be
employing some of the steps in the sequence above. In order to help you
develop the skills necessary for this process your second year practicals
have been broken down into a series of exercises, as under the headings
The first important point is that a scientific experiment must be grounded
in a theoretical framework, unless one is breaking completely new ground,
i.e. your hypothesis must be formulated from some knowledge base. In your
practical course your first task will be to complete a pre-test or preparatory
exercise covering the theoretical concepts which are essential for your
understanding of what you will do in the laboratory. You will need to read
your practical notes carefully beforehand, especially the Introduction,
as to establish which topic areas from your lecture material are relevant
and form the theoretical background. You may also need to revise basic
scientific or mathematical concepts from your earlier studies. An example
of a typical question is given below; it is taken from a practical on the
effects of thyroid hormones:
What is the effect of thyroid hormone on basal metabolic rate, and
how might this be manifested in relation to body temperature, appetite
and body weight?
This is another learning aid which can be used to cover background material.
As an example of such texts you should work through the model How to
Use a Programmed Text (see Appendix A), before attempting the
one which is relevant to the particular practical.
Even though you will not always have the opportunity to design your
own experiments, you need to be aware of the reasoning behind the ones
in your books. Each class has both a General Objective, or overall aim,
which is equivalent to the main hypothesis which you are going to test.
Each class also has a number of Specific Objectives, which detail different
aspects of that hypothesis, the various logical predictions from it, which
underpin the experiments. In some practicals you can add to this list with
your own hypotheses, and if time permits, actually carry out the experiments
to test them.
Experimental Method, Results and Discussionsections
will be discussed later.
The Background information on practicals summary in Part
II of the second year course guide is a useful comparison of the features
of different practicals.
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