Laboratory is a required
part of this course.
Both the lecture and laboratory portions of the course must be passed independently in order to earn a
passing grade for the course.
·
A lab report is due every week. The lab
report should be postmarked, faxed, e-mailed or dropped at my office (W4-46) no
later than the Tuesday after the week for which the experiment was
scheduled. Reports received late
will be down-graded.
NOTE:
1.
When on-campus, eye
protection MUST be worn at all times in the laboratory. There will be NO exceptions to this rule for any reason.
2. Prior to attending the first on-campus lab (during Week 3 of the course), the student must have completed, submitted and passed both the Safety Test and the Math Review worksheet which are listed as the Week 0 lab assignments. (See syllabus)
Pay special attention to the
instructions below on how to do a lab
report because if lab data is submitted without being
part of a report, you will automatically lose 40% of the lab report grade.
The lab report shall consist of 2 main
parts: an Experiment Report (cover)
sheet (which can be downloaded each week from WebStudy) and the data report forms from
the experiment itself.
1. The cover sheet (40% of report grade) contains basic information: your
name, partner’s name (if any), title and unknown number (if applicable).
Also, there are 4
additional, required parts (which
should be written or typed on the cover sheet): the Purpose, the Procedure,
the Theory and the Error Analysis
for that specific experiment. Expressing
yourself in a coherent and succinct manner and examining your data critically
are important skills
Purpose:
·
A brief statement of why you did the experiment. Specifically what were you trying to
accomplish.
·
A single sentence will suffice in most cases.
(Example…for Expt C: Solubilty the
purpose would be….
To
find the solubility of salt and sugar in water as a function of
temperature. To represent the results
graphically.
Procedure:
·
A brief step-by-step summary
of how you performed the lab. Even though you are summarizing, this will
probably take several sentences.
·
This section needs to be detailed enough
that a person
would be able to perform the experiment (repeat what you did) by following what
is written here.
(Ex: “Measure the amounts of A and
B used” would not suffice.
A correct statement might be: “
Samples of A and B, weighing about 5 grams each, were measured on the
balance.”)
Theory:
·
Theory means “why” so this section is an explanation of
the scientific principle on which the lab experiment/ technique is
based…….an explanation of the scientific
principle or law that the
experiment is designed to demonstrate…..an explanation of what makes the
experiment work so that your “purpose” is achieved.
·
The theory should be a
·
The theory can usually be
gleaned from the background information on a lab experiment. If the experiment involves carrying out a
chemical reaction(s), the balanced equation(s) should be given here as
well.
[For example, an experiment that deals with balancing equations has
as its scientific principle the Law of Conservation of Mass and what happens to
atoms during a reaction. Your theory section of this experiment’s
report would then focus on that. For an
experiment on gases, it might discuss the Kinetic Molecular Theory]
Error analysis:
·
A critical explanation and
justification of your
results.
·
You must think about your experiment and your results in order
to write an error analysis!
·
This should be a minimum of three thoughtful and
complete sentences in which you justify or explain how you
know (or why you believe) that your experiment worked well or was unsuccessful.
·
Try to explain/justify it quantitatively (with numbers) rather than
just qualitatively (with words) if possible.
·
If the experiment has a known
result, you should compare your
result to it (that is: do a % error calculation) and discuss whether the amount
of error in your result is acceptable or not.
(Under 5% error is usually considered acceptable)
·
If there are no known results to use for comparison, you can
refer to the internal consistency of multiple trials, etc. (Are trials 1 and 2 of the same thing giving
the same result…as they should be?)
·
If your results and/or experimental procedures could be improved (and
they usually can!), you should elaborate on how you would do this if you were
given the opportunity to repeat the experiment.
[For example….if 3 students working
as partners did 3 trials to find the Molar mass of unknown metal Z8 and their
results were 27, 23 and 31 grams/mole…..an error analysis might look something like
this…. The three trials to find the Molar
Mass of unknown Z8 were inconsistent.
The data ranged from a low of 23 g/mole to a high of 31 g/mole. In comparing these results to the MM of the
elements listed on the periodic chart, this would put the identity of Z8
between Na and S. Since elements P and S
are non-metals, they can be eliminated.
In addition, Na can be eliminated because it is too reactive to be used
without special precautions. That means
that Z8 is most likely Mg or Al, both common metals. If repeating this expt., in order to improve
the consistency of the results, I would…..blah, blah, blah…. ]
2. The data tables and calculations (60% of report grade)
·
These pre-designed pages can be removed from your lab book or from the
take-home experiment downloaded.
·
The blanks on the data pages should be neatly filled in with your
recorded data, calculations and results.
Feel free to add lines to these pre-designed pages as needed.
·
Make sure to show sample calculations.