8h - Rocks Flashcards
What forms when lava cools down quickly?
Igneous rocks with small crystals.
What is the outer layer of the Earth called?
The crust.
What is molten rock on the surface called?
Lava.
What happens to rocks during erosion?
Fragments of rock are moved by gravity, wind, water, or ice.
What forms when large bodies of magma cool down slowly?
Igneous rocks with large crystals.
What is chemical weathering?
When acidic rain water reacts with minerals in the rock.
What is physical weathering?
It happens because of temperature changes.
What is onion-skin weathering?
When heated and cooled rocks make cracks due to expansion and contraction.
What is freeze-thaw action?
When water expands as it turns into ice, making cracks in the rock wider.
What is biological weathering?
When rocks are broken up or worn away by plants and animals.
What can mining for metals cause?
It can destroy habitats and cause pollution.
What type of rocks can fossils form in?
Sedimentary rocks.
How do sediments form layers on the sea bed?
Rivers slow down when they enter the sea, depositing sediments.
What is cementation?
The process where dissolved minerals in water crystallize in gaps, sticking grains together.
What materials do we obtain from the Earth for building?
Stone, cement, and concrete.
What is an ore?
A rock with enough metal to make it worth mining.
What are unreactive metals found in?
Their native states.
What is the purpose of recycling metals?
To make supplies of metals last longer and reduce pollution.
