Rocks Flashcards
(18 cards)
What is the outer layer of the earth called?
The crust
What is the very centre of the earth called?
The core
What is the Earth’s core made of?
iron and nickel
What is the layer of the Earth called inbetween the crust and the core?
The mantle
how is igneous rosk formed ?
igneous rock is formed by magma or lava cooling down
how is metamorphic rock formed?
igneous or sediment rocks have heat and pressure which causes it to change into metamorphic
what is cementation?
when the bits of rock get stuck together
what is compaction?
the liquid is squeezed out
how do sedimentary rocks form?(3 steps)
1.deposition
2.compaction
3.cementation
Which type of rock contain fossils?
Sedimentary rock
how are the size of the crystals made
the slower the crystals are formed the bigger the crystals are
you can remember this by giving the crystals time to form
What is deposition?
Where small pieces of rock fall to the bottom forming a layer
Give an example of chemical weathering
Acid rain
Give an example of a rock that is eroded by acid rain
Limestone
Give 2 examples of biological weathering
tree roots and animal burrows
What is freeze-thaw weathering?
When water in the cracks between rocks freezes and expands making the crack bigger
What is onion-skin weathering?
Onion-skin weathering happens when it is hot in the day but cold at night. The change in temperature makes the rock expand and contract causing it to break.
Give 2 examples of physical weathering
freeze-thaw and onion-skin
