It is generally recognised that practical activities are an essential part of meaningful science learning. Scientific concepts and processes, cognitive skills such as problem-solving analysis and application, psychomotor skills such as observation, measurement and dexterity, may all be developed through practical experiences. Furthermore, positive attitudes to science and technology as subjects and to science orientated careers are often promoted through such practical activities in schools. Regrettably, large class sizes, limited resources, and other pressures on teachers, militate against practical laboratory or field work in many schools in the developing countries. In the past, formal practical examinations which were set and marked externally provided an incentive for pupils and teachers to do practical work during their lessons. Unfortunately, overseas practical examination requirements, and even local ones, are difficult to meet, in terms of equipment, materials and secure supervision. The new 'O' level syllabus for Zimbabwe, for instance, illustrates this problem, since it was originally intended to be examined by a practical as well as theory papers. This has never been implemented due to difficulties of financial and manpower resources, and supervision. Many other African countries are also faced with this problem. As a result practical examinations are very rare. ... The purpose of this study was to develop and try out some examples of low-cost practical experiments in biology, chemistry and physics with children from a local school. It was also intended to find out whether or not such low-cost experiments could be used as alternatives to more elaborate traditional 'O' level practical examinations, but still be appropriate tests of the requisite knowledge and skills.

Most science curricula in Africa include the development of scientific skills and processes in their aims. The intention is that a process approach should be adopted to the teaching of science. We have tried, through the approach described in these notes on the exercise Collecting and interpreting information, to focus on the development of some of these processes. The method involved collecting raw data on food, ingredients and food prices, computing aspects of these and recording the results in table or graphic form and finally interpreting these results.