Read the laboratory experiment and any suggested additional reading (s),
before
coming to lab.
Do the assigned pre-lab
exercises (if any). These generally cover any calculations
or important observations
which need to be made.
Make a list of questions
regarding the experiment. A simple question can save
hours of time in the
lab.
All data should be
recorded in a sturdy laboratory notebook. Do not use sheets of
paper or 3 ring binders,
as these pages can become quickly lost.
Make a brief outline
of the experiment in your notebook as a way of speeding up
getting started, including
calculations for needed reagents.
It is sometimes necessary
to modify lab procedures on the day of the lab to obtain
better results. If
you are prepared these changes should be easy to make.
Prepare data tables
ahead of time. Well prepared data tables not only speed up the
recording of data,
but also aid greatly during report writing.
Clean your glassware at the end of the period so it will be ready the next lab.
Many students waste
time washing and drying glassware only to find out the large
beaker they just cleaned
and dried will be used to boil water. THUNK THINK!!!!!
Many students are so
busy trying to get done they forget to write down their
observations. Color
changes, endothermic or exothermic changes, physical state
changes, boiling points,
melting points, freezing points, etc.
Look at the data, does
it look reasonable for the type of experiment? When in
doubt repeat a portion
of the experiment, there is no better teacher than finding
your own mistake.
If you are still unsure, the lab instructor should be able to help, ask
him or her.
Lab instructors will
sometimes discuss the important aspects of the lab with
students individually
or in small groups in an effort to help them get more out of
the experiment. Keep
your ears open and you may hear something that will help you
out.
Lastly, it is important
to follow the safety do's and don'ts of the laboratory, not
only for your own
safety but also your fellow classmates. Report the dangerous
lab practices
of others, you will be doing them (and yourself) a big favor.
Experiment Title
Although self explanatory, the title helps you, as the student, define
your understanding
of the laboratory experiment.
Purpose
A brief description (in your own words) of what scientific principle
is to be tested or
verified.
Procedure
A brief outline of the experimental procedure. (A detailed report of
all the steps taken is
not necessary. Your lab instructors have a copy of the laboratory
manual if a detailed
review is needed.) By including a procedure outline in the report
your attention is
focused on the what happened during the experiment. (A similar outline
is used as
preparation of the actual lab experiment.)
Data Collection
This is one of the most critical portions of the lab report. Without
good data recording in
the laboratory note book, completion of the lab write up beyond
this point futile or will
certainly seem so. Presentation of data in tables allows easy
following of the coming data
manipulations. Tables should be clearly labeled as to their content
and numbered for
ease of referral in the discussion section. (Table Examples)
Part of the data may involve making observations (color changes, temperature
changes,
melting point, boiling point, the physical appearance of a chemical
substance, etc.) The
observations requested in the lab experiment are the bare minimum
needed to perform
the experiments. Sometimes extra observations you make may provide
extra clues.
As an example: You are given a metal sample and told it was either
pure gold (Au) or
pure silver (Ag). The lab asks you to perform a series of chemical
tests, wouldn't the
metal's color give you a clue as to the its identity? Keep your eyes
open.
Calculations
One clear example of each different type of calculation should be presented
as a check
of your work. Do not include pages full of each and every calculation,
it just wastes your
time and paper. Who wants to read 3 pages of the same calculations
with different
numbers? Results might be presented as shown in this example.
Uncertainty/Error Analysis
We all generally regard our answers as absolute. This is fine for
expressions such as 4 +
5 = 9, where the exact solution is known. However, in the real world
of experimental
chemistry no results (or very few, if any) are absolute. Therefore,
some estimation of
the experimental uncertainty is necessary to help explain the results
and to verify if the
scientific principle tested holds. An example can be found here.
Discussion and Conclusion
This is an area which gives many students trouble. It requires looking
at the experimental
title, the purpose, the data and calculation sections of the
lab report and briging them all
together. Sometimes it involves the comparison of the student's experimentally
derived
answer to a known literature value. Other times, it requires the student
to identify an
unknown from a list of unknowns based on the information gathered
during the
experiment. (Discussion/Conclusion)
Often these 'known values' are provided for the student. When the answers
are not
provided it is up to the student to seek out the truth (UIC has an
excellent Science
Library along with a trained staff to assist in such information quests).
The World Wide
Web (WWW or W3) has become an electronic super highway of information,
with more
data added daily. Links to chemistry related web sites can be
found in the Chemistry
Resources page of this guide.