World in Motion: Earth's Tectonic Past and Future
Scientists attempt to reconstruct Earth's history so as to better understand the current state of geologic affairs, including those forces that cause plate movement.
World in Motion: Earthquakes and Plate Tectonics
With the advent of plate tectonics, it's become apparent that episodes of extreme geologic upheaval--like earthquakes--are much more than simply random events.
World in Motion: Heat, Convection and Plate Tectonics
Most scientists believe heat and convection probably play a major role in plate tectonics. And, yet, many questions remain.
World in Motion: Plate Boundaries and Plate Movement
Whether studying earthquakes, volcanoes, or other geologic events, scientists usually focus their attention on plate boundaries and plate movement.
World in Motion: Seamounts, Guyots and Island Arcs
Seamounts, guyots and island arcs form on the ocean floor as a result of a hot spot or mantle plume. While seamounts do not extend above the ocean surface, a guyot is tall enough to be eroded by wave activity and therefo..
World in Motion: Understanding Earth's Interior
Many scientists believe the plate tectonics process begins deep within the Earth. The challenge is to gather reliable data about an area that no one has ever actually explored--at least not directly.
World of Uncertainty: Changing Look of U.S. Society, The
The U.S. population is becoming larger, older, and more diverse at end of 20th century. Minority groups are forming their own collectives in order to define themselves economically, socially and politically. Feminist gro..
World of Uncertainty: Clinton's Impeachment and Acquittal
On December 19, 1998, voting along party lines, the House approves two counts of impeachment against Bill Clinton. The matter then moves to the Senate where a trial of the President, the first since 1868, begins in early..
World of Uncertainty: Clinton, Triumphant and Embattled
Bill Clinton rebounds from the mid-term defeat and is in a commanding position to win re-election. His greatest strength is the success of the economy and the reduction of the federal deficit. Conservatives argue that so..
World of Uncertainty: Election of 2000, The
After the relative quiet of Clinton's last two years in office, the presidential election of 2000 turns out to be one of the most controversial in American history. As television coverage of the election unfolds, Gore wi..