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<font face="serif">In general I will want you all to use Microsoft
Excal, OpenOffice, etc., to generate your graphs that have linear
relationships. This week, however, forcing you to do that could
be cumbersome. I have a comguter generated graph created on the
class website using the data from this lab -- and it took me a
long time to do it. My recommendation is that for this lab you
do it by hand on good graph paper (not the stuff in your lab
notebook).</font> You can also do it on your computer, but only
do one graph per sheet (unlike mine which had all six sets of data
on one graph).<br>
<br>
Here are the things I check for when I grade graphs:<br>
<br>
<ol>
<li>Are the axes in the right positions and appropriately labelled</li>
<li>Can I clearly see the data points</li>
<li>If there is a linear trend, is it indicated properly (never
connect the dots)</li>
<li>If a linear regression is done, is the equation on the graph
and easy to read</li>
<li>Does the graph fill the entire sheet</li>
</ol>
<p>Number five is a sticking point with me -- if you are making a
graph use as much of the sheet of paper as you can. Don't create
a graph that uses one quarter of the sheet of paper. Also, make
sure that your data fills most of the graph area. Don't obsess
over this -- but do try to do it correctly. If you would like me
to look at your graphs before you submit them for the first time I
will gladly do that Monday morning before class.<br>
</p>
<p>Now for the freezing point depression lab you will have to
essentially draw two best fit lines on each graph. I am not
asking you to do linear regressions at this time; just draw the
best fit line through the portion where the solution cools quickly
and then another line through the lines where it slows down (see
my example). Extrapolate these two lines to their point of
intersection -- and that is the freezing point.<br>
</p>
<p>Let me know if you have any questions.<br>
</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Mercer University, Macon, GA 31207 (478) 301-5627
<a class="moz-txt-link-freetext" href="http://faculty.mercer.edu/pounds_aj">http://faculty.mercer.edu/pounds_aj</a>
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