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This unit, developed by the Third World Science Project, is designed to add a multicultural element to existing science syllabi (for students aged 11-16) in the United Kingdom. The project seeks to develop an appreciation of the: boundless fascination of the natural world; knowledge, skills, and expertise possessed by men/women everywhere; application of knowledge and skills to solve the practical problems of everyday life; impact of modern technology in the world; and the influence of the cultural background on the perception of knowledge, problems, and solutions. The unit begins with a discussion of the viability of and technology involved in producing methane from waste materials, followed by information on: physical/chemical properties of biogas; basic theory of anaerobic breakdown of materials into methane; differences between aerobic/anaerobic methods in methane digestors; reproduction of the anaerobic process in air-tight containers; and role of different bacteria in the biological breakdown of wastes in digestors. A discussion of what kind of digestor should be built and best way of using gas/slurry produced follows. A report on the role of the integrated biogas system in Sri Lanka (illustrating benefits for a country lacking in fossil fuels) and a description of how small digestors can be constructed using school materials are included. (JN)

This unit, developed by the Third World Science Project, is designed to add a multicultural element to existing science syllabi (for students aged 11-16) in the United Kingdom. The project seeks to develop an appreciation of the: boundless fascination of the natural world; knowledge, skills, and expertise possessed by men/women everywhere; application of knowledge and skills to solve the practical problems of everyday life; impact of modern technology in the world; and the influence of the cultural background on the perception of knowledge, problems, and solutions. The unit begins with a brief survey of rural, traditional building and associated problems, using Datoyili (Northern Ghana) as an example of a loosely nucleated settlement of single-story huts. A plan of the village, chief's compound, and interior of chief's hut are included. Scientific concepts involved in building are then considered, such as advantages of cylindrical huts related to direction of sun's rays and use of the thatched roof as non-conductor of heat. Mathematical exercises related to these topics are included. Additional sections focus on construction/comparison of round/rectangular houses, importance of using local labor/materials in constructing houses, and other topics. The unit concludes with illustrated instructions for making models of round huts and rectangular dwelling. (JN)

This unit, developed by the Third World Science Project, is designed to add a multicultural element to existing science syllabi (for students aged 11-16) in the United Kingdom. The project seeks to develop an appreciation of the: boundless fascination of the natural world; knowledge, skills, and expertise possessed by men/women everywhere; application of knowledge and skills to solve the practical problems of everyday life; impact of modern technology in the world; and the influence of the cultural background on the perception of knowledge, problems, and solutions. The unit begins with an outline of the methods used in Zambia to produce charcoal from skillfully constructed log piles. An extract from the Technology Consulting Centre at Kumasi on charcoal burning follows, as well as a report of charcoal burning in Sri Lanka. A contribution on charcoal burning by a third year pupil of Lubushi Seminary in Zambia is included, together with some experiments on the small-scale preparation of charcoal. Suggested practical work includes collection of volatile vapors and the measurement of temperature porosity of charcoal. (JN)