Discussion Most, but not all earthquake activity occurs at the margin of the plates. At the end of the exercise the student has at least partially recreated the classic figure in Earth Science textbooks that shows the plate boundaries of the Earth. Our class investigates the greenhouse effect during a two week period. Table l is a summary of web sites, data, and tasks that are performed on-line. These data are plotted as a function of year in Figure 1.
Students see a rise in carbon dioxide in the atmosphere, but global temperature rises and falls.
There must be other factors at work, so it's on to the net. By searching web sites such as Volcano World, they see that average global temperature drops when significant volcanic eruptions occur. They discover that volcanic ash prevents some solar energy from reaching the Earth, and that this has an effect on the temperature of the Earth system. They begin to appreciate the interplay between the Earth's lithosphere, hydrosphere, atmosphere, and biosphere, not by lecture, but by meaningful, minds-on activities. The web is searched to find opposing viewpoints, and the module is capped by group reports on the Greenhouse effect.