Imagine secondary students inspecting bags of garbage, counting bottles and cans that their family uses in a week, or collecting the exhaust gases from the school principal's car. Odd activities for a science class? Not exactly. In fact a growing number of science teachers are designing lessons similar to the following:

• Organizing a recycling campaign in the school in which all cans, bottles, paper, plastic containers and bags, and newspapers are separated and recycled.

• Debating issues such as: In an environmentally sustainable global economy should most people ride bicycles (or use some energy efficient and environmentally safe form of transportation) rather than driving cars?

• Participating in an electronic international conference by linking classrooms around the globe with computers to discuss and exchange ideas with fellow students in other nations about environmental problems such as global warming, ozone depletion, acid rain or rainforest degradation.

• Engaging in a brainstorming session to identify environmental problems and issues that impinge on their lives. Teams of students will be organized to select one of the problems, and then plan a project in order to take action to solve the problem.

These and other activities similar to them enable secondary students to explore real issues in the classroom. The activities give a context for science learning---the local community, the school grounds, the water system in a school, an automobile, a local pond or lake, the local atmosphere. Although not limited to local environments, acting locally on problems that have relevance to students increases the chances for participation and action taking. These activities, and indeed this approach to science teaching has been called the Science-Technology-Society (STS) approach, and represents a major trend in science education for the 1990s. This chapter will be devoted to exploring STS not only from a theoretical point of view, but more importantly from the practical aspect of implementing STS in the classroom.

PREVIEW QUESTIONS

• What are the characteristics of environmental education and science-technology-society programs?

• What strategies do science teachers use to present STS lessons in the classroom?

• What are some of the significant STS themes, and how do teachers present them in the classroom?

• What are some STS curriculum examples used in today's secondary science classrooms?

• How are STS modules evaluated? Are there criteria that science teachers agree on?