Some chemical changes occur naturally in the environment.
Others may be produced from the human use of products and processes that result in pollution, environmental destruction, and ultimately may involve some level of risk to human health or to the survival of other organisms. By exploring fertilizers, pesticides, acid rain, the nitrogen cycle, the carbon cycle, the water cycle, and other types of chemical reactions in the local environment, students begin to distinguish between those chemical reactions that are beneficial and those that are harmful. Through collecting, analyzing, and interpreting data on environmental quality, students begin to assess the impact of chemical pollution on the local environment and suggest ways of solving these problems. Students research acid rain and make a presentation on its effects. The research could include how acid rain is formed, and the major sources of the chemicals that react to form acid rain.