| PREVIEW: Work alone or with one partner. Find a substance which
hypothetically is high in protein. Do a dinky experiment to estimate its protein
content. Hand in typed report by end of lab period; better
yet, attach a file of your report to an email to jannr@queens.edu
by the end of the lab period. The most important things
you are supposed to learn are
- how a simple experiment can test a simple hypothesis (in science,
simplicity is elegance!)
- how to write a semi-professional report either alone or with your co-author [SECTIONS REVIEWED BELOW and on the
column on the right on the report form
page]
- that some structural characteristics of different types of biological molecules allow us
to detect their presence.
- that tiny little details can ruin your experiment.
- that really getting the scientific method is really important in this course.
DETAILED INSTRUCTIONS
INTRODUCTION:
Choose one or more of the samples [milk, egg substitute, shampoo, soup, or whatever you
want to test], and write a hypothesis about its protein content in comparison to the
control, which is ordinary egg white [a high-protein food]. When you write the
introduction section of your report, you should also write something about why you
expected the substance to be high [or low] in protein and maybe something about why we
should even care to bother to read the rest of the report. After you understand the procedure just
below, write a prediction of the specific results you should expect
if your hypothesis is correct. What should you expect to see in the
experiment?
PROCEDURE:
As you do the experiment, keep careful records of what you do. Then, later, write
exactly what you did in such a way that another student could repeat this experiment
exactly the way you did it. Write as though you were telling an ordinary story
[declarative mood, past tense, active verbs], not as though you were
writing instructions like this [imperative mood]. Do NOT list all the materials you
used, but clearly identify everything so that your experiment could be replicated by
someone who reads your report. Try to be concise but clear; tell who did what [avoid
passive verbs!] but not why [usually].
Here's what you will actually do [and why you should do it this way]:
You can detect protein with the biuret reagent, which you could mix yourself by
combining equal amounts of 1% CuSO4 (copper sulfate) and 40% NaOH (sodium
hydroxide). The biuret reagent changes color in the presence of protein (as demonstrated
by the instructor). Notice that this kind of experiment is best done with two controls--a
positive control to show how the reagent changes when protein is present and a negative
control to show what the reagent looks like when it's treated exactly the same but in the
absence of the protein. You can also make some rough comparisons about relative quantities
of protein by judging that the color change is less [or more] intense in the sample than
in the control. If the sample has a very strong reaction, sometimes the sample and
controls can be diluted (equally, of course) and the test repeated for better comparisons.
Now predict what specific results you should get if your hypothesis could be true and
write the prediction for the "Introduction" section
above.
RESULTS:
Keep a good record of what happened. Then explain it in a sentence or so.
The ideal "Results" section says, "The results are shown on Figure
1." Then attached to your report is a graph titled, "Figure 1. Protein content
of parakeet feathers." Or you could write, "The results are shown on Table
1," and attach a chart titled, "Table 1. Protein content of sophomore
skin." Or you could just write it out in a paragraph.
CONCLUSION:
Write again [or paraphrase] your prediction. Describe how
your results matched [or did not match] your predictions. Then state that you reject [or
cannot reject] the hypothesis. Discuss further, if appropriate.
REFERENCES AND NOTES: [possibly not needed for this report]
Like "end-notes" in an English composition paper. Separate bibliography is
unnecessary. (If you use information from the Internet in your report, be sure you
cite it properly in your "References and Notes" section.
See the report help page
for help.
TITLE Don't forget to put a title at the top
of your report. Your name(s) and the date should also be
at the top of the report, location at your discretion (below
the title and centered or above the title in one of the
corners). Do not use a separate cover page for this
course. In fact, save a lot of paper and submit your
paper electronically as an attachment to jannr@queens.edu.
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