Patten, J. M.

Explains how trash threatens the environment and discusses what can be done to end pollution.

Studies the dangers of toxic waste and discusses how the problem can be corrected and prevented.

Studies the dangers of water pollution and discusses how the problem can be corrected and prevented.

Discusses how oil spills harm the environment and explains what steps can be taken to prevent spills and clean the land and animals after a spill occurs.

Describes the effects acid rain has on the environment and discusses what can be done to correct the problem.

Studies the dangers of air pollution and discusses how it can be prevented.

Explains that age is indicated in terms of numbers and determined by counting; then shows that age is measured in time periods, generations, and life spans.

Discusses the inch-pound system used in the United States to measure size, weight, height, and distance and the metric system used for the same purposes elsewhere.

Discusses the development of numbers and systems of counting to answer the question "How many?".

Explains such concepts as money, currency, paper money, banks, and banking services.