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February 2001, Vol. 4 No. 1 Print Ready ArticlePrint-Ready
Aims of Laboratory Teaching
 
Professor Vijay Gupta
Indian Institute of Technology, Kanpur
 

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:

  1. Teaching of the experimental method (EM),

  2. Supplementing the theoretical material covered in the lectures, i.e., essentially as a teaching aid (SL), and,

  3. 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).

TABLE 1
Specific Aims

Familiarisation with
• standard equipment
• measuring technique

EM
EM

Illustration of
• physical phenomenon
• concept taught in lectures

SL
SL

Teaching of
• attitude to experimental work

EM

Providing
• closer contact with faculty
• stimulation to independent thinking
• feel of R & D labs

IA
IA
IA

Training in
• observation
• deduction from observation
• critical awareness
• keeping lab notebook
• writing reports
• acquiring specific information

EM
EM
EM
EM
EM
EM


Next, we need to look at the cognitive levels of various objectives. For this we use Bloom’s 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.

TABLE 2
Bloom’s Taxonomy for Objectives in the Cognitive Domain

Level 1

Knowledge

Level 2

Comprehension

Level 3

Application

Level 4

Analysis

Level 5

Synthesis

Level 6

Evaluation

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 these needs.

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.

General Instructions

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.

 
 
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Aims of Laboratory Teaching
   
Demonstrations and Active Learning During Lectures