Subject: report calc. and graphs and Excel

You can use Excel to do calculations and graphs for both
pre-labs and reports.

If you make the Excel worksheets look like the report
forms in the lab manual(including titles and headings)
you can print them and turn them in for the report form.
You do not have to copy the numbers to the report form in
the lab manual.  You still need to show sample calculations
just as if you weren't using Excel.

Always put 1 graph only per page.  Make sure it fills up the
majority of the page and your axes are scaled properly so your
data occupies most of the space of the graph (don't leave a
lot of empty space).  Your graph does not have to start at the
origin (the 0,0 point).  Your Title and axis labels shouldn't
be so big they take up too much space.
The "Example of a Good Lab Report" found at the link below
shows an example of a good graph.

https://uglabs.cbc.osu.edu/gc-labreport

When it states to draw a smooth curve "through" the data
points it doesn't literally mean the line needs to go through
every data point.  You are supposed to be doing a "best-fit"
curve, which may be curved or straight (most of the time it
will be a linear fit; a straight line).  Many times you will
find the line doesn't go through any of your data points.

When doing the graphs using Excel each graph still needs to
occupy the whole page (with small margins of 0 inch), as
is the case when not using Excel.  Use a 10 or 12 pt type for
the axis labels and titles.  You do not need a legend if the
graph has only 1 set of data.  You should always have Excel
print the equation for the line and the correlation coefficient
(the R^2 value).  If the exp calls for determing the slope of
the line you get that from Excel.  For the sample calculation
of the slope you simply need take a couple of points off the
line and use them to calculate the slope.  However, use the
Excel generated slope for further calculations if required.

Take a look at my example for using Excel for exp 14.
I show how to program equations into the "cells" in Excel
so it can do the calculations for you.  I also show how to
get more than 1 set of data on the same graph (which you will
need to do for several exps).  Remember, this is just an example
and not meant to show you every single step or to show you
exactly how everything should look (the sample graph is
incomplete).

You still need to worry about significant figures and units
both in the tables and graphs.  It's not too hard to set the
sig. figs. for your data in Excel tables.  For instance, lets
say all your numbers in a column should have 3 decimal places
(using the instrument in lab you could take readings to 3 decimal
places).  You will need to set this column to 3 decimal places.
Highlight the column, right click, chose "format cells", set it
to a "number" and choose 3 decimal places.  Sometimes it's not
this easy to do and you may have to choose "scientific notation"
instead of "number".  There may be a few numbers you have to set
separately to a different number of decimal places so the they
have the correct s.f..  You will need to highlight these separately
and follow the procedure above.

Generally, when using Excel if you set the number of decimal places
correctly to give the correct number of s.f. in your tables before
making the graphs this will automatically be transferred to your
axes on the graphs.  Otherwise you will need to edit the axes to
set the s.f. correctly.

You can use Excel for exp 6 to plot the points, draw in the
best-fit lines and text boxes.  You should NOT have it do a trend line.
You should have it draw lots of gridlines and then draw the lines for
Ti, Tf and the vertical line (time of addition) by going to "Insert"
and inserting lines and textboxes.

If you use Excel, you are not to share the Excel files with each other.
You must do the work in Excel yourself.  Don't think we can't tell when
students share Excel files.  We can and that's academic misconduct.
You can ask someone to help you learn how to use Excel but should not
have them do it for you.

You do not have to use Excel for anything.  You can use other graphing
programs and do the calculations by hand and make a table in Word for
the data (report sheet).  However, I think most reports will be a lot
easier and more quickly completed if you do.  Use it to create your
report sheets.  Pretty much anytime you have a lot of repeated calc.
you can make use of Excel to do the calc. for you and anytime you have
a lot of graphing it's a good thing to use.  It's fairly simple and
straightforward.  Save your work often.  If you can't figure out how
to do something look around or click the right mouse button and some
sort of window will usually pop up.  If you make a mistake your
computer will not explode.  You can always get back to what you last
saved.


Dr. Zellmer