Questions at this higher cognitive level require critical examination of the material in the module. They may require additional information from print or web-based resources.

Science

1. What conclusions can be drawn from the observed trend in the series of ãpurple Octobersä? Click here to see images of Antarctic ozone levels for every October between 1979 and 1996.

2. Examine the electron density maps for Freon 11 and 12 given in the reading Why is Ozone Disappearing? What do the colors indicate?

3. The initial step in the destruction of ozone takes place in the upper atmosphere where normal oxygen molecules are hit by high-energy photons, breaking the normal oxygen into two oxygen atoms. These atoms, in turn, react with other oxygen molecules to make ozone. Represent each of these steps with an equation and also with spheres as shown in the ãcreation of ozoneä movie.

4. Are the beads used in the activity ãChecking for UV Radiationä sensitive to visible light? How do you know?

5. Why can a gas chromatograph be used to separate various atmospheric pollutants but cannot be used to separate the components of seawater?

6. Select the conclusion about ozone concentrations that can be supported by the graph below?
   

   Graph of the change in ozone concentration with altitude.

   1. As altitude increases, the concentration of ozone steadily
   2. As altitude decreases from 60 km, the concentration of ozone first rises and then steadily falls until the surface is reached.
   3. The concentration of ozone is fairly constant throughout the first 60 km from the earth; this is what is meant by the term the "ozone layer."
   4. There is a region of maximum concentration of ozone between about 10 km and 30 km; this is what is meant by the "ozone layer."

7. In the spectrum below, the wavelength range of ultraviolet radiation is shown in light purple. Why might this be misleading?
   

Science and Society

1. Your cousin states that there is no need to worry about ozone depletion because everyone knows that breathing ozone is harmful. Do you agree with that point of view? Give some specific reasons for your position.

2. A stranger on a bus tells you we shouldn't worry about the effects of global warming caused by the greenhouse effect that are predicted by computer models because computer models were very inaccurate in predicting the effects of CFCs on the ozone layer. Do you agree with that point of view? Give some specific reasons for your position.