Physics 101 Astronomy
Spring 2009
Homework due 2/27/2009
The extremely high temperature of the Earth’s core causes material in
the surrounding mantle to become hot, expand, and rise toward the
surface. The mantle material cools by transferring heat to the crust,
sinks, and the rising and sinking together produce a circular motion of
material moving beneath the Earth’s surface. This circulation of
mantle material causes the continental and oceanic plates to move
across the Earth’s surface. At various locations, we are able to
observe the plates colliding, separating and moving horizontally.
The drawing below shows a cross section of the Earth’s surface and
its underlying mantle. At this particular location, the dense oceanic
plate is being forced beneath the less dense continental crust. The
dense oceanic plate experiences higher temperatures (and pressures)
as it is forced deeper into the mantle. This interaction between the
two plates causes them to partly melt and some of that molten
material moves upward through the continental plate, forming
volcanoes.
Oceanic to Continental Plate Convergence Zone
1. In the drawing above, which way (right or left) are the oceanic and
continental plates moving? The oceanic plate is moving to the
right and the continental plate to the left. This is indicated by
