The teaching of laboratory courses in engineering and science
is perhaps the weakest links in the chain of education. Touted
as components essential for giving a practical orientation
to education, there appears to be a lot of confusion regarding
their aims and objectives. For an instructor, laboratory teaching
is a low-priority job which does not contribute to his professional
development, is largely boring and repetitive and to which
his students are completely apathetic. The students view laboratories
as boring but cool components of their curriculum,
not intellectually challenging but involving multiple chores.
But unfortunately, in spite of constant lip service paid to
it, nothing much is attempted to improve the situation.
Many colleges complain about the lack of resources, modern
equipment and infrastructure as the factors responsible for
the malaise. This is true, to a degree, but not the whole
story. It is believed by some that the root cause of the problem
is a lack of clarity of the objectives and the resultant poor
design of the pedagogical contents of laboratory instruction.
These objectives can be classified into three categories:
- Teaching of the experimental method (EM),
- Supplementing the theoretical material covered in the
lectures, i.e., essentially as a teaching aid (SL), and,
- Incidental aims (IA).
An attempt has been made to classify the various possible
specific aims of laboratory instruction into the above three
categories (c.f. Table 1 below).
|| Specific Aims
concept taught in lectures
attitude to experimental work
closer contact with faculty
stimulation to independent thinking
feel of R & D labs
deduction from observation
keeping lab notebook
acquiring specific information
Next, we need to look at the cognitive levels of various
objectives. For this we use Blooms taxonomy for objectives
in the cognitive domain (c.f. Table 2). It is quite difficult
to assign the levels to the various objectives outside a specific
context. Various persons at various levels, from technicians
to researchers and even Nobel laureates, conduct experiments
and therefore, depending upon the context, the cognitive level
of an experiment should change. The level of the various objectives
for experiments in a teaching laboratory should depend on
who is being trained. Thus, a technician being trained to
do routine well-defined experiments needs training only at
levels 1 and 2 or, maybe 3. But the training of engineers,
if carried out at such low levels, is not going to lead to
any meaningful development of the requisite skills. It is
believed that the present state of the all around dissatisfaction
with laboratory teaching in the engineering colleges arises
essentially because of the low levels in the cognitive domain
that the various teaching objectives are aimed at.
for Objectives in the Cognitive Domain
It appears that the present day laboratory experiments are
largely aimed at reinforcing the lecture material and not
to teach the experimental method, which should be the logical
aim of a laboratory course. The two aims are indeed quite
conflicting. The first calls for a large number of experiments
while the second calls for large amounts of time for experiments,
the two being necessarily opposed. Similarly, if a large number
of experiments are to be conducted, detailed instructions
must be given so that students do not waste their time. But
the teaching of experimental methods needs time for self-discovery
with little set instructions, if any.
A major problem with all lab experiments is that they do
not attempt to challenge students sufficiently and the whole
exercise is at a rudimentary level. Vital aspects such as
designing the apparatus, decisions on what measurements need
to be taken and what variables need to be controlled are not
addressed by the students. In fact, a student has no control
on the experiment, including how the tests are to be conducted
or how the accuracy is to be estimated. Students are given
no opportunity to think for themselves.
It must be understood that familiarity with standard equipment,
measuring techniques and use of standard calculating procedures
are essential, but are all part of lower-order learning. Carefully
developed demonstrations, videotapes, etc. can easily fulfil
The training of an engineer requires higher-order learning
of the experimental method at the analysis, design and evaluation
levels. An experimental course should teach students that
(1) there is an experimental methodology, (2) it is field-independent,
(3) it is reliable, and (4) it should be followed through
with students making decisions at each stage from formulating
the objectives to analysing the results.
I recently had an opportunity to teach a course on Experimental
Aerodynamics and reformulated the instructions to the various
experiments. The sample below gives an extract from the general
instructions given to the students before the course.
You are required to complete a set of experiments
as detailed below. A new strategy is being attempted
this term in which only the broad goal of each experiment
is given to you. You will be required to plan your experiment
around the equipment being made available to you. For
best results you are advised to study the available
equipment before the date of experiment, and to talk
to the instructor. Make sure you understand the range
of physical variables available to you for control and
to plan your experiment in details before you come to
the lab for experiment. Discuss your plan with your
instructor before you begin. He may suggest modifications
or he may not, depending upon his judgement as to the
learning value of any mistakes that you might make.
This strategy has been adopted in the hope that
it will offer you more control of the decisions that
need to be made in any experimental investigation and
that it may lead to a more efficient learning about
the experimental method, which is seen as one of the
more important learning objectives of the course.
Planning of an experiment requires fixing the values
of the various parameters that control the experiment:
speeds, diameters, angles of attack, etc. These are
usually fixed depending on the range of non-dimensional
similarity variables of interest. Therefore the first
thing that needs to be done while planning experiments
is to determine the range of control parameters available
to you, and then decide the values that you are going
to use so that the similitude parameters are within
the desired range.
As it is made amply clear, the students are not spoon-fed
the procedure. They devise their own theory, measuring strategies,
number of measurements, and formulae to be used. The process
takes a lot of effort, heartburn, exploration, errors, and
accusations, but ultimately produces the joy of discovery.
Another deviation from the previous courses was requiring
the students to make calculations of the error bounds using
standard procedures for single-step experiments and for multiple-step
experiments using statistical procedures. It was found that
this perhaps is a single most educative step in a laboratory
course where the students understand the limitations of their
data, procedure and equipment.
The general instructions also include the following:
In addition, each
student is expected to submit TWO experiments written
up as formal reports, as if they were communications
to a technical journal. The format specified for the
technical notes in the AIAA Journal is to be followed.
This would count for 20 points.
I can confidently state that the course run was quite satisfying
to both myself and the students.
In conclusion, it is important to look seriously at the aims
of laboratory exercises, and to verify that there is enough
there to teach at the higher levels of the cognitive domain.
It is important to recognise that the primary aim of laboratory
instruction is to teach the science and art of experimentation.
Another core aim of a laboratory course is to teach students
the art and science of experimental error estimation to guide
them in planning better experiments. Another incidental purpose
that a lab can fulfil is to teach formal written communication.