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Activity Guide
An Atmosphere of Change
Ask students the following questions:Start this program discussion by explaining that the scientists in this program are working to answer many questions about the environment. From the ozone layer to the Arctic Circle, from San Francisco in the West to the St. Lawrence River in the East up to the highest level of the atmosphere, they are testing, exploring, and making discoveries.
- How safe is the air we breathe?
- The water we drink?
- The soil under our feet?
- How do we find out about damage to the environment and prevent further harm?
Keith Miles, Ph.D., national biological service
Dr. Miles is a marine ecologist and an expert on the effects of pollution on wildlife. As an African-American child growing up in Washington, D.C., Dr. Miles didn't see much wildlife, but he loved nature programs on television. Today, most of his work is done outdoors - his work takes him from San Francisco Bay to the Aleutian Islands. One of the ways he tests the health of the ecosystem is to monitor levels of toxins in the tissue of mussels, a staple food for the birds in the area. The toxins that build up in their tissue can travel up the food chain, so studying mussels can provide clues about the health of other species.
Discussion and Activities:
- Dr. Miles' focus on mussels as the subject of his study raises the importance of protecting the lowest level of the food chain. Discuss this concept with the class. How does damage at the lowest level affect animals higher in the food chain?
- The scientists studying bald eagles in the Aleutians are concerned about thinning eggshells as a sign of a possible threat to the birds. Why is this a problem? To show the effects of thinning eggshells, have groups of students soak raw eggs in a glass of vinegar (a mild acid) overnight. Have them check the eggs daily and describe their observations.
Mario Molina, Ph.D., professor of atmospheric chemistry, Massachusetts Institute of Technology
Dr. Molina grew up in one of the most polluted cities in North America, Mexico City. As a young chemist at the University of California at Irvine, Dr. Molina and the founder of the university's chemistry department were investigating the effects of chlorofluorocarbons, or CFC's, on the upper levels of the atmosphere. CFC's, used in aerosol cans, air conditioners, and other products, are stable in the lower atmosphere, but the scientists suspected that they might break down in the upper level, the stratosphere. When they found that their theory was correct, they also found that CFC's broke down into a dangerous chemical - chlorine - which destroys the protective ozone layer. For years, Dr. Molina and his colleagues presented their data, trying to halt the use of these dangerous chemicals. Finally, their efforts paid off. Today, he continues his research and continues to make discoveries.
Discussion and Activity:
The ozone hole and the effects of CFC's on the stratosphere have been a feature of news stories for many years. Have the students look for recent articles or information about international regulations, new studies, or predictions about the future of the ozone layer and present their findings to the rest of the class.
Karen Medville, Ph.D. candidate in environmental toxicology, Cornell University
Ms. Medville is finishing her Ph.D. studies in environmental science at Cornell University in New York. She also spends a great deal of time doing volunteer work in the Native-American community. As a member of the Cherokee nation, Ms. Medville wants to be a role model to young people. Each summer, she volunteers with a Mohawk community, teaching science. Her research focuses on the effects of lead poisoning. Lead poisoning has long been recognized as a cause of brain and neurological damage, especially in children. Most children in the United States are tested to make sure the lead levels in their blood are below the acceptable level. Ms. Medville is conducting tests on laboratory rats to find out the effects of very low levels of lead in the body.
Discussion and Activities:
- In this program, Ms. Medville discusses some of the choices she made as a young woman and as an adult, and explains why her work is so important. Today, she spends a great deal of time working with young people. After they hear her story, ask the students to discuss the message she gives to young people, both in her words and in her actions.
- As an environmental scientist, Ms. Medville must be able to work in several fields of science, including chemistry, biology, and physics. As the class watches her in various work situations, discuss the various fields of science that are demonstrated, and how they overlap in environmental science.
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