Lesson 2: Volcanoes
Concepts:
- Constructive (forces that create) and destructive (forces that
destroy) forces, which include volcanic eruptions, create
landforms by adding new material to the earth’s surface.
- Magma is molten rock beneath the earth’s surface.
- Magma that intrudes into fractures in rock can change the
shape of the earth’s surface.
- Lava is magma that has reached the earth’s surface.
- Lava flows, cools, and hardens on land and under water, forming
layers of new rock.
Vocabulary:
- Magma: molten rock beneath the surface of the Earth
- Magma Chamber: a cavity containing gas-rich liquid magma
that feeds a volcano
- Lava: magma that has reached the surface through a volcanic
eruption; streams of liquid rock that flow from a crater or
fissure
- Lava Dome: a steep-sided dome that forms at the top of a
volcano when thick, cool magma emerges from the volcanic
opening
- Lava Flow: Lava that flows quickly over the surface of the
earth and covers a wide area
- Caldera: an oval shaped volcanic imprint that forms when
magma erupts from a shallow underground chamber
- Pillow Lava: balloonlike mounds that form when lava erupts
under water or empties into the ocean.