Learner Express: Modules for Teaching and Learning
Volcanologist Dave Sherrod of the Hawaii Volcano Observatory, USGS, and Michael Manga, Associate Professor of Hydrogeology at the University of California, Berkeley, describe how mantle rock melts into magma and how the more buoyant, liquid magma floats toward the Earth's surface. They also compare the amount of dissolved gases in Hawaiian volcanoes versus Mount St. Helens. Different compositions of magma create shield volcanoes and stratovolcanoes. Gas-enriched, higher-silica eruptions create classic stratovolcanoes, while the less-gaseous, low-silica magma in the Hawaiian volcanoes erupts to create shield volcanoes. Run Time: 00:07:00
Grades 5-8 Standard D. Some changes in the solid earth can be described as the "rock cycle".
Two Different Kinds of Volcanoes
Demo of Shield Volcanoes Versus Stratovolcanoes