Consider the following five
elements in constructing an effective pre-lab introduction:
A. Concepts
Begin the pre-lab introduction
by going over some of the related concepts from lecture. A pre-lab assignment
often addresses these concepts and can be a great jumping-off point
for the introduction.
Discuss with students how
these concepts relate to the lab exercise at hand. Using class discussion
or small group work can help your students make links between theories
or principles and lab practice.
Help students make connections
between the concepts addressed in the lecture portion of the class,
and their applications in the lab exercise. As the students begin the
experiments or procedures, they should understand what principles and
concepts are being illustrated through the lab. Students should never
leave the lab not understanding why they did what they did.
In
some labs, especially in upper division courses, the students are critically
involved in planning and executing the lab. For example, advanced students
may be asked to design and carry out their own experiments. In these situations,
students should have the conceptual basis needed to design experiments
that test hypotheses directly related to the scientific theories or ideas
in question.
B. Experiment/Procedure
Briefly go over the lab
procedure with the students before lab begins. This helps students to
focus on the tasks and goals associated with the lab exercise. It can
also be another opportunity to help students connect theory and practice,
as you explain the concepts behind each phase of the lab experiment
or procedure.
Put overviews or lists of
tasks on the board to help students navigate their lab exercises. Be
mindful that the lab experience should be a discovery process and should
not feel like following a cookbook.
Discuss the scientific method
(at least once during the semester) to help guide students through the
lab experiments. This is especially important, as mentioned above, if
students are designing the experiments themselves.
C. Data Analysis and Interpretation
Review examples of data
analysis with the students before the lab in order to help them later
make sense of the data, or...
Give the students hints
about data interpretation and allow them to work on sample data in groups
or with lab partners. The pre-lab assignment
can be helpful here as well: give students sample data to analyze and
interpret at home, and use this as another discussion point during your
pre-lab introduction. They will have had practice in data analysis and
interpretation before coming to lab.
D. Equipment and Safety
Considerations
Give a short lecture or demonstration
on lab safety, and chemical and waste disposal. It is your responsibility
to make sure that students are prepared to conduct the lab in a safe manner.
E. General Tips
Choose an effective format
and use it consistently every week: You will probably think first about
format when planning a pre-lab introduction. It is usually helpful to
you and the studentsto select and use a consistent and effective format.
The students will then know what to expect every week in lab, and they
can turn their attention to the concepts and procedures involved in
each lab exercise. Using a consistent format also makes it easier for
you to to organize and plan the pre-lab part of the lab section.
Think about time considerations:
One of the most important and difficult apsects of the pre-lab introduction
is the length.
How much time will you
spend introducing the material before students begin the lab? It
can be difficult for you to balance the desire to make sure students
have all the information they need with the desire for a succinct
introduction that will leave plenty of time to carry out the lab
exercise.
The amount of time spent
on a pre-lab introduction will vary depending on the material being
presented, so it is difficult to recommend a time limit. Be aware
that students tend to get frustrated and anxious to begin the lab
if the pre-lab introduction is too long. Striving for an effective
presentation while being brief is a sound (and challenging) goal
for a pre-lab introduction.
Use discussion and interaction
as part of the lab introduction: Lecture is not the only format for
introducing lab material. Often, working in small groups or having a
class discussion is more effective in challenging your students to think
about the lab. Students often learn as well or better from each other
than they do from the instructor alone.
In
some labs, especially in upper division courses, the students are critically
involved in planning and executing the lab. For example, advanced students
may be asked to design and carry out their own experiments. In these situations,
students should have the conceptual basis needed to design experiments
that test hypotheses directly related to the scientific theories or ideas
in question. 
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