T he Department of Physics, NUS, has adopted a new approach in the teaching of practical physics to First Year undergraduates. This new method centres on a 45-minute discussion held prior to each practical session during which students are encouraged to explore various ideas and make use of commonplace knowledge towards the planning of a proposed experiment. Instead of readily accepting standard practices, students are engaged in problem solving and the added discussion enhances their appreciation and understanding of physics experimentation.

The Reasons for Change

We started using this new approach due to the limitations of the traditional physics practical. A traditional lab session usually begins with a brief description of the apparatus and the experiment to be performed. Next, students muddle through a set of written instructions, obtaining and analysing data (that can sometimes be derived from reading their seniors’ lab reports) and making feeble attempts at error analysis.

Despite encouragement from teaching staff, the traditional physics practical often fails to motivate and challenge students to learn science by discovery. Instead of concretely grasping the feasibility of their measurements, students tend to leave each session with a vague impression of the apparatus and methods they have used. For instance, First Year undergraduates generally fail to grasp the scale of basic physical quantities such as length, speed, density, etc. They barely know the difference between a micrometre and a millimetre or whether 100 volts is a lot harder to generate than 10 volts, even after they have made measurements with micrometer screw gauges and voltmeters.

In addition, because course work emphasises lectures and textbooks rather than practical work, students tend to regard lab sessions as perfunctory exercises to be performed to satisfy modular requirements. Consequently, learning takes second place to completing measurements as well as becomes a process of assimilating well-established facts that may be applied to a few hypothetical problems. So while teachers may be convinced that the laws of physics are founded on experiments and that experiments are an integral part of a physics education, it takes a great deal of effort to persuade students to be more enthusiastic towards laboratory learning.

Our Solution

The failure of the traditional physics practical to promote deep learning is not an indictment of educators who certainly do not lack effort or ability. In truth, the problem is a universal, age-old one as experiments that can challenge students to utilise their creativity are very difficult to design, particularly at the freshmen level.

In our attempt to overcome the limitations of traditional physics lab sessions, we have decided to focus on how the broad objectives of an experiment (usually one that measures a physical quantity or verifies a certain law) are to be met with a given set of apparatus. In other words for each experiment, we carefully assess its instructional value and highlight the critical aspects of experimentation that are important for it to work (see example). We then use these points to outline a discussion plan and rehearse the progression of practical ideas that will be introduced to the students in the course of discussion. The result is that students are confronted with an aim to realise the experiment and a problem to be solved with practical knowledge.

The discussion invariably begins at ‘how’ to arrive at a general scheme to attack the aim (or how to develop an overall strategy for engaging the problem). This then moves on to consider ‘what’ can be used in specific components of the set-up and ‘why’ some equipment are more suited than others for the experiment. Along the way, students are asked to draw upon their daily experiences and practical knowledge (e.g. the size of large mirrors, the highest rpm of rotating wheels, the wavelength of light) and make quick back-of-the-envelope estimates for essential quantities. They are encouraged to think of practical solutions from scratch, without recourse to standard procedures as far as is permissible. Following the discussion, they then perform the actual experiment (i.e. the regular experiment). In this format, the preceding discussion gives students a renewed perspective to perform the practical.

Feedback

We have been pleasantly surprised by the end-of-semester feedback showing how popular this new approach is among students. Although there are detractors who would rather get on with finishing their experiment quickly, most students indicated they:

• enjoyed the practical sessions (some found the practicals were stress-free);
  
• were encouraged to participate actively in the discussion because of the relaxed atmosphere;
  
• gained an appreciation for the magnitude of physical quantities and their measurement;
  
• found they were more curious and aware of their surroundings;
  
• felt that the new approach reinforced what they learnt from the lectures.

Conclusion

We believe that that success of using pre-practical discussions depends heavily on the presence of enthusiastic teachers/facilitators who possess the necessary handle on physical problems and strong familiarity with practical instrumentation. When supported with the necessary expertise, the approach can be easily adapted for other experimental sciences.

More importantly, we have realised from this discursive approach that teaching practical physics need not be confined to performing an experiment with a given set of equipment and instructions to follow. Conducting a task-oriented discussion first with the students helps to focus their minds on the actual practical session that follows. In the discussion, the critical aspects of the experimental set-up are given real consideration and students can express their ideas without reserve. Although colleagues may argue that throwing students into the deep end (i.e. giving them minimal instructions) is the best way for them to learn, our experience thus far seems to indicate that local students do better when provoked into thinking. Hopefully, the benefits that students have gained from our laboratory will stay with them for some time.