05:54
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.
01:05
Differences Between Oceans and Continents (Part 1)
Geophysicist and geologist Tanya Atwater talks about the very different ways in which oceans and continents are formed and how each changes over time.