Rocks
What is a rock?
granite and rhyolite
How are lava and magma different?
Lava is molten rock that reaches the surface, while magma stays under the surface.
What is intrusive vs. extrusive rocks?
Intrusive = inside the Earth
Extrusive = outside (on the surface) of Earth
What rock formation is shown on pg. 86?
Ship Rock (Tse Bit'a'i)
True/False: If an igneous rock is dark, it has a low level of silica.
False
If you add heat and pressure, you'll end up with what rock?
metamorphic
How do igneous rocks form?
Name two things that lie beneath Earth's thin layer of surface features.
solid and molten rock
How many rock samples are on pg. 77?
True/False: Intrusive rocks reach the surface as forces inside Earth push them up.
True
What percent of Earth's crust is igneous and metamorphic rock?
95%
obsidian and coal
Which rock is most common at the surface and why?
sedimentary rock; the process that forms these rocks occurs at the surface (loose material getting pressed together)
Why are intrusive igneous rocks so strong?
They are formed inside of Earth and have a long time to grow hard.
What forms from the lava that comes out of a volcano?
extrusive igneous rock
What U.S. state is shown in the photograph on pg. 161?
North Carolina (my home!)
What two ways do scientists use to classify igneous rocks?
the texture and composition (silica levels)
The speed of magma cooling determines what?
If lava is high in silica, how will it erupt and spread?
It erupts explosively and spreads slowly because it is thick and sticky.