Earth Revealed

The latest offering from the Annenberg/CPB Project is devoted to understanding our home (in the largest sense): the planet Earth. Designed to serve as an introductory course in geology, the series is hosted by geologist and professor Dr. James L. Sadd. We watched programs number 12 and 16, Minerals: The Materials of Earth and Mass Wasting, respectively. In Minerals, viewers learn that there are over 2,000 varieties of minerals on earth, although only two dozen are common. After defining what minerals are, Sadd and interviewees discuss the different types of minerals, the various ways in which they're formed, basic properties, and how some minerals have played an important role in the political, economic, and technological history of mankind (gold and silicon, for instance). In Mass Wasting, we learn that terminology has been changing over the years. What we used to call a landslide is now referred to as a "mass wasting event." A landslide is just one of the more obvious forms of mass wasting, with slower forms such as "creep" and "slump" occurring all the time yet not perceptible to the untrained human eye. The causes and treatment of mass wasting are covered, as well as practical examples of the effects of the process--particularly in California, where some pretty nice real estate has moseyed down the slopes, prompting California citizens to devise some rather ingenious methods for keeping their homes intact. Other programs in the series include: Earth's Interior, Plate Dynamics, Earthquakes, Volcanism, Groundwater, and Glaciers. Although not as immediately accessible as some previous efforts from the Annenberg/CPB Project, this series does present a current and in-depth introduction to geology, and would be excellent for high school and college libraries. It is also recommended for public libraries with larger video collections. (Available from: The Annenberg/CPB Project, 901 E Street N.W., Washington, D.C. 20004; 1-800-LEARNER.)