Practicals in Applied and Environmental Chemistry

T van Ree
A workshop organized and presented at
ICCE16

Budapest, August 2000

The decision in 1999 by the academic management of the University of Venda to change its teaching paradigm to one of problem-oriented, project-organised, group-based learning, has impacted not only on the theoretical contents, but also on the way the practical programmes are run in the Department of Chemistry.
 

1 Why practical work?

With the increasing availability of computer simulations, and the rising cost of chemicals and equipment, we are increasingly being criticized by the nonscientists for the strong emphasis on practical work. We may offer some of the common responses (Bennett, 2000), such as: However, the majority of our first-year students will not pursue chemistry as a career. Is it then appropriate to design a practical programme that is directed at the training of professional chemists? Therefore, the objective of our first-year practical course is to introduce students to the  work that chemists do, so that they can experience the constraints and potential of the chemical investigative process.

Traditionally our students study problems isolated from technological and societal aspects.  In an attempt to narrow the academe-industry gap, we introduce students to more real-world technical and ‘consumer' chemistry. In the senior undergraduate years in Applied and Environmental Chemistry no attempt is made to introduce the latest technical innovations, but rather to concentrate on the approach to laboratory-based investigations and developing professional skills (Dunn et al., 1998) related to the materials, food and environmental fields.
 

2 Attention overload (Boice, 1993; Kellogg, 1987)

In our university, first-year science students typically experience up to 30 formal contact hours with Science courses per week, consisting of 10 to 14 lectures, four hours of tutorials and nine to 12 hours of practical. Add to this the recently introduced ‘University-wide core modules' African Civilization, Scientific Method and Theory of Knowledge, and English Communication Skills, and we have a very full programme indeed! In the second and third years, students have eight to 12 lectures, two hours tutorials or seminars, and 15 hours practical work. Compared to students in the human sciences, who have little more than 15 contact hours per week, our science students have little time for reflection, working on assignments and projects, and writing up practical and project reports. No wonder that many excellent minds are permanently turned off by the sheer amount of work, which often also tends to be pretty boring to the non-chemist.

In our first year modules, laboratory activities tended to focus on purely chemical topics, dominated by the manipulations which must be mastered, especially titrations. The number of titrations has now been greatly reduced as it is doubtful whether any of these students will ever need to be an expert titrater.

Like all Science students, Chemistry students have to reorientate themselves several times within a day. Therefore, it is no wonder that they tend to compartmentalize learning even within Chemistry, so that they perceive the chemical kinetics taught in a Physical Chemistry module as something different from the kinetics discussed in an Organic Chemistry module. It is in the laboratory where student misconceptions can become particularly transparent, and where there is the possibility to emphasise the integrated nature of all chemistry.

Instead of training students in manipulating equipment, handling chemicals or developing techniques, our aim in the applied and environmental practicals is rather to train students in problem-solving investigation, in experimentation. We would like our students not only to do an experiment, but also to devise that experiment. This brings the student closer to the real world of research.

In the real world, the researcher has an idea or a problem, or develops a hypothesis based on prior experience, observation, reading papers or by discussions with colleagues. From this comes an idea for an experiment, a test or a preparation that might support or refute the hypothesis, provide data for further speculation, produce a desired product, or provide problems for further study. Only once the experiment has been designed does the scientist enter the laboratory with a plan or ‘recipe'. In many practical courses the student also enters the laboratory with a recipe - but he or she does not own it. Seldom is the student given the chance to devise an experiment, and practicals usually turn out to be relatively simple (and even boring) exercises.
 

3 Successful practical work

Some manipulative training is essential, but more practical programmes should enable students to enter into a pre-lab process of: Even in the first year it should be possible to give students a more ‘real' sense of what chemical investigation is about. Post-lab reflection is even more important, so that more than a written report on the work done should be submitted. Students should be given the opportunity to evaluate their work and that of their peers, to discuss the strengths and weaknesses of their approach, to analyse the data critically, design follow-up experiments and reflect on the learning that occurred. This means that less time will be spent in the laboratory doing actual work, but in our opinion the time will be better spent. Reports from industry confirm that desirable employees are not necessarily the strong, academically and experimentally skilled workers, but rather the quick learners, critical and creative thinkers, problem solvers, communicators and team players.

A skills analysis grid will help to pinpoint skills that are being overemphasised in the current practical programme and those that are being neglected. It will also help to change the emphasis from ‘topics' to skills. Where laboratory instructions are provided, write them in such a way that the reader will be able to follow the different phases in the investigation, instead of just following a recipe.
 

4 What makes a good investigation? (Denby, 1998)

In a freeform, procedureless laboratory programme (Warren & Pickering, 1987) the right choice of investigation is critical to its outcome. Therefore, a good student investigation: Here are some of the kinds of investigations that can be fruitful:


Some kinds of investigations, when handled carelessly, can prove disappointing, such as:

5 Some things to do

Activity 1:
Your group has just been informed that a local plant, Dilocomotum nautilum, used for many years by herbalists to treat malaria, contains a compound, Dinautilactone, which is highly effective against malaria. The potential for earning a substantial income from the exploitation of this plant seems obvious.
Given that everyone in your group makes a contribution (collaborates), your task is to:
  1. Identify the types of information you will need for planning in order to utilise this opportunity.
  2. Identify the potential sources of information.
  3. Draft a plan of action.
  4. Report back.
Activity 2:
Some basic human needs are the needs for food, health, clothing and shelter. Given that everyone in your group makes a contribution, your task is to:
  1. Discuss one of these needs and the contribution chemists can make.
  2. Gather some background material that will enable you to come to a realistic formulation of a problem or topic to investigate, using your present skills (as a second-year Chemistry student).
  3. Design the investigative process and experiment.
  4. Consider practical and safety aspects.
  5. Report back.
Activity 3:
The right to a clean and healthy environment has been declared a basic human right.
  1. Discuss the implications for all chemists and try to identify some topics for chemical research.
  2. Develop a realistic problem formulation for an investigation covering one of these topics, using your present skills (as a third-year Chemistry student).
  3. Design the investigative process and experiment.
  4. Consider practical and safety aspects.
  5. Report back.
Activity 4:
As part of a study to compile an integrated environmental management plan for the Luvuvhu River catchment area, the Department of Chemistry has been given the task to evaluate possible chemical pollution hazards in the catchment. Using 1:50000 maps of the area, identify some of the possible point and diffuse sources of pollution, and propose a research plan to monitor pollution of the river. Specifically mention which substances, in your opinion, should be monitored, why, and how they should be measured.
 

References

  1. Bennett, S.W. 2000. ‘University practical work: Why do we do it?', Educ Chem, (March), 49-50.
  2. Boice, R. 1993. ‘Writing blocks and tacit knowledge', J High Educ, 64(1), 19-54.
  3. Denby, D. 1998. ‘What makes a good investigation?', Educ Chem, (Jan), 17-18.
  4. Dunn, J.G., Kagi, R.I., and Phillips, D.N. 1998. ‘Developing professional skills in a third-year undergraduate chemistry course offered in Western Australia', J Chem Educ, 75(10), 1313-1316.
  5. Kellogg, R.T. 1987. ‘Effects of topic knowledge on the allocation of processing time and cognitive effort to writing processes', Memory and Cognition, 15(3), 256-266.
  6. Smith, M.E., Hinckley, C.C., and Volk, G.L. 1991. ‘Cooperative learning in the undergraduate laboratory', J Chem Educ, 68(5), 413-415.
  7. Warren, W.S. and Pickering, M. 1987. ‘Student strategies in a Junior-level procedureless laboratory', J Chem Educ, 64(1), 68-69.