This study investigates two issues: a) the usefulness of indigenous technology as an approach for teaching science and technology to junior pupils of secondary schools in Sierra Leone. b) the factors which influence its implementation. In order to carry out this investigation, the author developed a fifteen lesson module on energy, using the 'coalpot', a significant indigenous technology device as centre-piece. The module was tried out in three schools in Sierra Leone, using a total of 224 pupils. Other members of the sample were experimental teachers (who taught the module) and non-experimental (who only evaluated it) and science educators. Using the triangulation method, data were collected by achievement tests, questionnaires, structured and unstructured observations and informal discussions. The results were statistically analyzed using the SPSS/PC and Minitab Computer packages. It emerged from the findings that indigenous technology is a useful approach for teaching science to junior secondary school pupils, irrespective of the problems encountered. The post-achievement test results show that on the whole, the module had a positive effect on pupils' learning. The study also shows that indigenous technology has the potential to generate pupils' interest and improve their attitudes towards science. The factors which can become barriers to the implementation of an innovation like this one, were identified and shown to be teacher- and school-related. It is recommended among other things that science education researchers, teacher trainers, curriculum developers and teachers collaborate to develop and document instructional materials based on indigenous technology. That indigenous technology be incorporated into teacher training methodology courses so that trainee teachers will have a longer period to become familiar with both the content and the teaching strategies that may be used.