Change in the Ozone Layer
Scientists have not been collecting data about the ozone layer long enough to make concrete decisions about its long-term effects. Using satellite imagery, students get an idea of the magnitude of annual changes in the ozone layer. Ozone levels are measured in Dobson Units, a measurement of the thickness of pure ozone at normal sea level temperature and pressure. Thus 100 DU equals 1 mm. of pure ozone at sea level.
Determine the fate of atmospheric ozone over Antarctica.1. Discuss with students how ozone levels are measured. 2. Examine one image of ozone concentrations above Antarctica and determine how the different ozone levels are depicted. 3. Starting with the earliest image, trace the magnitude of the ozone hole (if it exists) onto the graph paper and label it. 4. Continue with each subsequent year, noting whether or not there was an increase or decrease in ozone levels. 5. Discuss the trend observed and possible causes. If you had only given the students a few images, would this analysis have reached the same conclusions? 6. Discuss the importance of using satellite imagery in the analysis of the ozone hole. Antarctica is a difficult environment for research, at best. Satellite imagery makes it easy to cover the atmospheric changes on a daily basis. This also allows scientists to examine the changes over time. ChlorofluorocarbonsChlorofluorocarbons are the chief cause for the decline in the ozone layer. Have students research sources of CFCs and examine the chemical reaction that causes the breakdown of ozone. Are there any chemicals that could halt this reaction? What potential problems can be caused by introducing an additional chemical into the atmosphere? |
satellite images of ozone concentrations over Antarctica from the last 10 years, graph paper, colored pencils
