Air pollution, pesticides, water pollution, and population are the main topics treated in this teacher's guide, one in a series of Intermediate Science Curriculum Study (ISCS) materials. Part One of the book contains the student text with subject information, questions, and activities. Teacher notes in the margin indicate emphasis of the chapter, major points or concepts presented, questions to generate, activities to complete, procedures to follow, equipment needed, if any, and excursions or other experiences to supplement the reading material. Part Two develops the excursions keyed to each chapter and is designed with the same format as Part One. They are usually experiments or studies that can be completed in the classroom using other types of resource materials. Numerous pictures, line drawings, charts, and diagrams are placed throughout the text. (BL)