chemistry - rocks Flashcards
What are rocks made of?
Different grains that fit together.
What are interlocking grains?
When grains fit together with no gaps
What types of grains are sedimentary rocks made of?
Big grains so they crumble easily.
How are ignious rocks formed?
When magma/ lava cools
How are intrusive igneous rocks formed?
When lava cools slowly (e.g granite)
How are extrusive igneous rocks formed?
When lava cools quickly (e.g basalt)
How are sedimentary rocks formed?
When sediment accumulates overtime (there are often lots of layers in this)
What are metamorphic rocks?
Rock that had been changed by extreme heat and pressure
If a rock has bigger crystals it means that it cooled at a. ____
Slower rate
Which one cools slower, magma or lava?
Magma cools slower because it is situated within the earth, where it is insulated by other rocks.
What could cause rocks to break into smaller pieces?
Weathering and erosion. When it rains it causes the crystals in rocks to slowly degrade and erode.
What 3 processes occur when sediment enters the sea or river?
- deposition ( rocks are moved to the sea)
- compaction ( rocks are squished together)
- cementation ( rocks harden against each other)
What is physical weathering?
Due to changes in temperature or physical forces e.g waves and wind
what is Chemical weathering?
By chemical reactions (rain— acid— alkali)
What is biological weathering?
By the actions of plants and animals (humans and animals digging up dirt)
