For the independent research projects you will design and conduct a short physiology experiment. Table 1 lists the most commonly studied topics, but this does not exhaust the possibilities, it just gives an idea of what can be most easily done. The experiments could compare the effect of different treatments on some measurable feature. Alternatively, you could compare different groups of subjects (ie. men vs. women, athletes vs. non-athletes, reptiles vs. mammals etc...).
Table 1. Topics or experimental systems typically investigated in the first project :
Human reflexes Earthworm neurons Frog muscles (smooth and striated) Human respiration and metabolism Metabolic rates of small animals Active transport by frog epithelia
We have different transducers for measuring
a wide variety of factors. In addition to the force and movement
transducers we have pressure transducers, temperature transducers,
light
intensity transducers, pulse (heartrate) transducers and chest
expansion transducers. Many things can also be measured without
the use of electronics. We also have a video camera and analysis
VCR for monitoring movements.
The projects should be simple. They typically
require the equivalent of three lab periods to plan and execute.
These are not original research projects; you do not need to do something
that has never been done before. Also, your sample sizes will probably
be low (~5 subjects per treatment is a ballpark figure, depending on the
complexity of the treatments, and the size of your group). This means
that you probably won't get definitive answers. It is also not necessary
to do library research. I don't expect a complete synthesis of the
topic, I am primarily interested in your ability to design, conduct, and
analyze an experiment.
Your first step is to decide what you want
to study and develop a hypothesis. You should think carefully about
what you will measure. A common mistake students make is that they
want to collect data on a lot of different variables. One year a
group studied forearm muscle contraction in humans. They looked at
the effect of body size, athletic training, smoking, and gender.
They considered the threshold for contraction, the velocity of contraction,
and the force. Because of the small sample sizes and large number
of variables, they got a lot of confusing results and the project lacked
direction. To avoid this, choose one specific variable to test, and
try to eliminate all other possible sources of variation. Do this
by controlling other variables. For example, the group I just described
would have been better off comparing the threshold for muscle contraction
in athletes vs. non-athletes. They could have eliminated variation
caused by all the other factors by using similar-sized, non-smoking males.
That way, if they found an effect, they would know it was due to the difference
in athletic level, and could not be attributed to gender, size etc...
The point of the exercise is to learn good
experimental technique, analytical skills and how to present results in
a meaningful way. Therefore, what I am looking for is a well-defined
hypothesis, a carefully designed procedure to test this hypothesis, and
a clear, succinct write-up describing the experiment and analyzing the
results. Think of all the variables that could cause error
and eliminate them. For instance, if you are looking at human metabolic
rates, make sure your test subjects start in the same physiological state
(ie. 2 hours after lunch, resting, not taking medication...).
Experimental subjects:
You can use human subjects as long as there
is no risk involved. Each person in your group can probably recruit
at least two friends to participate. If you want to use animals,
we can get rats, frogs, bugs, worms and other small animals within reason.
Experiments other than those listed at the top of the page involving vertebrate
animals have to go through a review board. The paperwork requires
only about 2 paragraphs of writing and is not bad, but it will take at
least two weeks to process and you cannot start until the approval comes
through. So if you want to work with vertebrate animals, and have
an unusual project in mind, you should save that for the second project,
and get your proposal in as soon as possible. You probably won't
be able to justify any procedures that require significant discomfort to
the animal. If possible, use invertebrates in your experiments.
You will probably not be able to get a very
large sample size. Sample sizes in the past have ranged from five
to thirty subjects. In some projects, it is easier to run a large
number of tests than in others. If your data is easier to get, I
would like to see a larger sample size. If it is hard to get, I will
understand and judge your project accordingly. A larger sample size
is necessary for good statistical analyses, but this is often not practical;
we don't want to kill off large numbers of animals for our small laboratory
projects, and no matter how charming you are, most people can't convince
twenty or more friends to spend a few free afternoons in the physiology
lab. Do the best you can though, it will make your data more fun
to interpret.
Write-ups and presentations:
The write-ups are typically around 4-5 pages
(double spaced). You will not impress me with a long paper.
I am looking for a write-up that is detailed and thorough, but concise.
It should be well-organized. You should use standard scientific format;
this means having separate sections titled Introduction, Methods, Results,
Discussion. Click here for a detailed description
of what these sections include.
We will devote one lab period to group presentations.
Each group will have 5-10 minutes to describe their experiments.
The presentations will not be graded, but there will be some form of reward
for the best presentation (as voted by your peers). After each presentation
there will be time for questions. The point of all this is to give
you experience communicating your results to a group, and to give you a
chance to get feedback and possibly new ideas from your peers.
Click
here for suggestions on how to give a good presentation.
Details:
Work in groups of two or three. I will
expect a little more lab work out of a group of three students than a group
of two (larger sample sizes, for example).
When you have an idea for a project, meet
with me to see if it is feasible (you can meet with me anytime to bounce
ideas and possibilities around, even if you don't have a clear idea of
what you want to do).
Your grade will depend on the quality of your
experimental design, and the clarity of your write-up. These two
factors go together. A confusing report will make the experimental
design look haphazard; a haphazard design will lead to a confusing
report.
Deadlines:
Feb. 9 or 10 (after lab) - Submit a rough outline stating your
hypothesis and describing your experimental procedure. The outline
should be less than one page. It will not be graded.
Feb. 25 - Submit a draft of your final write-up. I suggest
that you get a draft in before this, if at all possible, so that you will
have more time to make revisions.
March 2 or 3 - Presentations
March 6 - Final report due - (late reports will be subject to
a minimum 10 point penalty)