7th Grade Science Chap 3
Terms
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- volcano
- a weak spot in the crust where magma comes to the surface
- magma
- a molten mixture of rock forming substances, gases, and water from the mantle
- lava
- magna that has reached the surface
- ring of fire
- a major volcanic belt that encircles the Pacific Ocean
- diverging boundaries
- plate boundaries along which volcanoes form
- island arc
- a string of islands that were created by a volcanic hot spot
- hot spot
- an area where magma from deep within the mantle melts through the crust above it
- Where are most of Earth's volcanoes found?
- mostly along plate boundaries
- How do hot spot volcanoes form?
- when magma erupts through the crust and reaches the surface
- element
- an element is a substance that cannot be broken down into other substances
- compound
- a compound is a substance made of two or more elements that have been chemically combined
- physical property
- any characteristic of a substance that can observed or measured without changing the composition of the substance
- chemical property
- any property of the substance that produces a change in the composition of matter
- viscosity
- the resistance of a liquid to flowing
- silica
- a material found in magma that has formed from the elements of oxygen and silicon
- Pahoehoe
- a hot fast moving type of lava that hardens to form smooth rope-like coils
- aa
- a slow moving type of lava that hardens to form rough chunks
- magma chamber
- the pocket beneath a volcano where magma collects
- pipe
- a long tube through magma moves fro mthe magma chamber to the earth's surface
- vent
- the opening through which molten rock and gas leave a volcano
- lava flow
- the area covered by lava as it pours out of a volcano's vent
- crater
- a bowl shaped area that forms around a volcano's central opening
- pyroclastic flow
- the expulsion of gas, ash, cinders and bombs during an explosive volcanic eruption
- dormant
- describes a volcano that is not currently active but may become active in the future
- extinct
- describes a volcano that is no longer active and is unlikely to erupt again
- shield volcano
- a wide gently sloping mountain made of layers of lava and formed by quiet eruptions
- cinder cone volcano
- a steep cone shaped hill or small mountain made of volcanic ash, cinders and bombs piled up around a volcano's opening
- composite volcano
- a tall cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials
- caldera
- the large hole at the top of a volcano when the roof of a volcano's magma chamber collapses