All experimental work consists of preliminary
planning, carrying out the experiment, keeping a record of the observations and
results, and finally evaluating and reporting the results. Your lab notebook is
like a diary of your experiments. It is important to keep a good notebook, as
you will refer to it when writing your lab reports and when taking the lab
quizzes.
The notebook must be bound (no
spiral bound or loose-leaf notebooks allowed). The most useful types have pages
with a grid or lines. It is
recommended to use a notebook with carbonless copyingÑeach page is doubled so
that a copy of your work is made, with one page perforated for easy
removal. Only pages designed for
removal should be torn out. Always
write in ink in your notebook so that the data cannot be altered. Water insoluble
ink is highly recommended. If you make a mistake, put a neat line through the
error and record the correct information. This allows referral back to the data
if it turns out to be useful later. Make a brief note about why you made the
change. Removal of pages from notebooks or altering of data with whiteout is
viewed as fraud
in the context of laboratory research.
Organize your notebook. Write your
name on the front cover and inside the cover. If page numbers are not already
present, number all pages in the notebook before writing anything else in them.
Leave the first few pages blank for a Table of Contents. Enter experiment titles and page
numbers in this table as you do each experiment. Start each experiment on a new
page, leaving a few blank pages at the end of the previous experiment if you
still have work to do on it. Avoid running experiments together in your
notebook. As long as they are properly labeled, you may mix pre-lab lecture
notes with experiments in your notebook, or you may wish to take the lecture
notes at the end of the notebook in a separate section. If you have unused pages once your work
is completed, write in large print ÒThis page intentionally left blankÓ so it
is clear that no data has been omitted deliberately.
Organize yourself by doing the
preliminary write up for each experiment. Plan your work before you come to lab
so that you can utilize the lab period most efficiently; for example, using
"dead time" while your reaction is heating for other procedures. Each
experiment will be recorded in your notebook in labeled sections as noted
below. This will constitute an informal ÒreportÓ of the experiment.
The originality of the notebook
content is vital to the integrity of you as a scientist. (See lab policy in
syllabus for explanation of the word original.) All sources used for pictures,
diagrams, or physical data should be properly referenced. You may not photocopy
material from the lab text into your notebook, with the exception of apparatus
diagrams (no captions) and spectral reference tables. Any plagiarism issues in your notebook will be treated
as dishonest academic conduct (see syllabus). Do not copy material from other students. Small portions of text may be cited from
legitimate resources, if a proper citation is used.
**Before you come to lab each
week, read the lab
textbook pages found in your syllabus AND any Techniques (in the green TOC textbook) listed
before the procedure section of the experiment. Note from the syllabus whether
we will be following the miniscale or the microscale procedures. Then prepare your notebook using these
sections. A formal typed-report will have these same sections that are found underlined.
1. Write the Title of the
experiment on a new right-hand page of your notebook. Give the appropriate
reference (e.g. Mohrig lab book, page 59). Enter the title and notebook page number for the
experiment in your table of contents.
2. The Purpose of your
experiment should be summarized in a few sentences. Although the purpose is
short it is still important, as all scientific experiments are designed to
answer a specific question or questions. You must determine what that question
is and phrase it as a concise, passive-voice statement. You should also give
the name of the methods (techniques) used to accomplish the purpose. ÒCaffeine will be isolated
from tea by extraction ÉÓ is much better than ÒWe will learn how to get
caffeineÉ " or ÒI will isolate caffeine É ".
3. Make a table of the structures and
appropriate physical data of compounds used, prepared and isolated.
Include the molecular weight, boiling and/or melting point for each reactant
and product, densities for liquids, and concentrations for solutions. These
values are referred to as literature values or theoretical values. Information on using physical data
handbooks appears on pages 27-31 (Technique 4) and Appendix (p. A-1) of TOC. You need to include data for
solvents and reagents, not just the reactants and products. This information can also be found on the web; for example,
Material Safety Data Sheets (MSDS) provide a wealth of information that
includes physical properties and safe handling of the substance. Chemfinder.com
also is a great source of information.
The Aldrich
catalog and CRC
index will be available at all times in the laboratory.
4. For lab experiments that involve the
preparation of a substance (a synthesis), include a balanced structure-equation
for the reaction that is to be performed. If a series of reactions is used to
prepare a substance, include all of them. Reactions that produce multiple
products or by-products can be problematic: in some cases, an unbalanced
equation with major and minor products should be written with the reaction
stoichiometry clearly explained underneath.
5. Write your Procedure. A
useful method is to first draw a vertical line in your notebook to divide the
page into two columns, making the line about two-thirds of the way from the
left hand edge of the paper. Use the wider column on the left to write a
detailed list of the steps you will follow in the laboratory in your own words.
This can be in complete sentences, written as a list of instructions, or
whatever works best for you. Remember that a picture is worth a thousand words
when trying to describe lab set-ups. You should write your procedure so that
you do not have to look at your textbook while performing the experiment. The
blank right hand column will be used during the lab to write procedural
changes, observations and data. Before beginning the experiment, you may want
to write down blank lines on which to record certain numerical data. In a
formal typed-report, the procedure section will stand alone, without the second
column.
6. Prepare a table for your results
section now so that you know exactly what is required during the laboratory. In
many cases, organic labs do not involve recording an extensive amount of
numerical data; this can often lead to a difficulty in finding the one or two
important numbers that constitute the final result. When a result table
is clearly separated from other parts of the experiment, you will know what values to record and share
with your partner before you leave lab each week.
**During your experimental work
each week you
should complete these notebook sections.
1. Write the date on which you are
performing the experiment and the name(s) of your lab partners at
the top of the right hand column of your procedure section. If you
complete the lab on a different date, make sure that you write in that date
next to the appropriate part of the procedure.
2. Use the right hand column of your Procedure
section to record all data and observations that you are asked to
record or that you think might be important. Also use this space to note any
changes or additions to the procedure. Try to record the data as close as
possible to the corresponding part of the procedure. If you are not sure
whether or not to write down a given observation or piece of data, remember
that another student in the class should be able to repeat the procedure
exactly as you performed it by referring only to your notebook. To avoid
deductions, write this information only in your notebook, rather than on your hand, paper
towels or the lab bench. Each person is expected to have a complete set of data
in his/her notebook; this way you won't be out of luck if your lab partner
suddenly drops or ÒflakesÓ.
Some examples of data and
observations are reagent amounts used, even if you use the amount in the lab book; time
and temperature of
heating, cooling, or reaction; changes in color or temperature during reaction; general
appearance observed
during a reaction; actual (experimental) boiling points during distillations; approximate amounts of solvents
or drying agents
used; amount of product obtained or isolated (both crude and purified, when
appropriate); physical characterization of the substance produced or isolated (appearance,
melting or boiling point reported as ranges, any chemical tests or
spectrometric data);
the look on your partner's face when informed that you just dropped the reaction
on the floor, etc.
3. More extensive data that won't fit
neatly in the right column of the procedure section should be recorded below
the procedure section. This may include spectral printouts, chromatograms, or
other tabular numeric data. Outside pieces of paper that are included in your
notebook should be attached with tape, staples, or glue-stick. Formal
typed-reports will have a distinct Data and Observations section.
4. Before you leave the lab, make sure
that your instructor checks and signs (or stamps) your notebook.
**After the experiment is
finished, quickly complete these sections:
1. Perform any necessary Calculations,
including calculation of theoretical and percent yields for synthesis
experiments, Rf values for thin layer chromatography, and percent
composition of a mixture from gas chromatography. Show your work in this
section. Make sure that you show the final result(s) in this calculations
section, as well as in the results section.
2. When appropriate, provide Spectral
Analyis of the information obtained from spectra and chromatographs. This
section should include the meaning of the spectrum or chromatogram, and a
summary table when appropriate.
3. Complete the Results section
for your experiment with all the required numbers. Then, simply state whether
or not you achieved the goal(s) set forth in your Purpose. This can be
by completing the numerical table you made before lab and/or by writing one or
two sentences that simply state the result. For example, "Cyclopentene was
obtained in 86% yield from cyclopentanol using the procedures described ÉÓ
4. Write the Conclusion section.
This is the most important part of your notebook and formal typed-report.
Whether or not your experiment worked as planned, you must justify the result
you just wrote (see #3) by summarizing and clarifying the physical, chemical,
and instrumental data you obtained. (Is it the product you expected? Why are
you sure?) For example, ÒThe product contained a carbon-carbon double bond
based on the infrared spectrum; in addition, a positive bromine test was
obtained, verifying this conclusion. The infrared spectrum further indicated
the absence of the cyclopentanol starting material, as there was no O-H stretch
in the IR spectrum. Furthermore, the boiling point observed was within 5û of
the theoretical value ofÉ"
Also in this section, make comments
about how effectively you were able to follow the planned procedure. You must explain how mistakes made affected
the outcome, and why deliberate procedural modifications were made during the
lab and their effect your result. If you failed to obtain product or only got a
miserable yield, try to explain why. Indicate any procedural modifications that
could help future experimenters, remembering that increasing the reactants
ten-fold is not an option in a microscale experiment. Remember to write this
section from the view of the experiment, not the experimenter. It is not appropriate to write "I
learned to perform extractions and had a wonderful and fulfilling experience."
Separate the various conclusions
into paragraphs for ease in reading.
5. Look over the Questions from
the lab text. It is appropriate (but not required) to answer them in your notebook
and use them during lab quizzes. You may also wish to visit office hours to get
a clearer answer to these questions.