Importance of distinguishing clearly between wave velocity and group velocity is discussed. Examples are used to elucidate both concepts. (DF)

Although many experiments to detect gravity waves are underway, and others are planned, so far none of them has reproduced Joseph Weber's results, first reported in 1967. (Author/DF)

The three equally valid usages of democracy in the modern world are not true democracies but simply different types of democratic government, making the teaching of democracy a difficult task. (Author/JB)

Discusses a model for explaining the spread of human population explosion on North American continent since its discovery 12,000 years ago. The model may help to map the spread of Homo sapiens throughout the New World by using the extinction chronology of the Pleistocene megafauna. (Author/PS)

Relevance creates a dilemma for the teacher because solutions to problems are controversial in contemporary society. It is argued that students still need to explore these problems and hopefully they can come to understand and appreciate the situations, and can comprehend the alternatives. (DF)

Problems concerning energy shortage are presented along with possible solutions. Three important areas of concern are (1) energy-origin and uses, (2) environmental effects of energy use, and (3) resources and new sources. (DF)

Fuel cells have several advantages over conventional ways of producing power. A brief explanation of operating principles, structure, and economic considerations is presented. (PS)

A study is presented to show ways by which management can stimulate technological innovation. (DF)

Articles are included concerning industry and schools, science and mathematics award scheme, teaching and research, safety, inservice training, Ugandan chemistry, plastics, and 19th century Nuffield. (DF)