Rocks Flashcards
What are grains?
Small particles of rock. They can be smooth, round or interlocking
What are crystals?
A solid material where atoms are arranged in an organised and regular pattern
What are the three types of rock?
Igneous, sedimentary, metamorphic
What does porous mean?
Has pockets of air meaning water can pass through it
What are metamorphic rocks like?
They have grains, thin layers and squashed fossils
What are igneous rocks like?
Crystals, non-porous, hard
How are igneous rocks formed?
Magma from under the earth cools down and solidifies on the earth
How are intrusive igneous rocks formed?
They cool slowly inside the volcano because of the heat meaning it has more time to form bigger crystals
What type of crystals do intrusive igneous rocks have?
Big - because of the heat, they have a long time to cool
How are extrusive rocks formed?
The magma cools quickly outside the volcano on the cool surface meaning the crystals are smaller since they don’t have as much time to form
What are sedimentary rocks like?
Layers, rounded grains, porous, soft, fossils
What causes acid rain?
Combustion of fossil fuels and coal and oil. They release sulphur dioxide when burned. It dissolves in raindrops and becomes sulfuric acid
What problems does acid rain causes?
They change the pH of water (more acidic) and makes fish die.
They change the characteristics of soil making the trees and plants die. This means photosynthesis gets reduced so the amount of oxygen decreases and CO2 increases
Also erodes and damages rocks and metals
What is physical weathering?
When rocks are broken down by forces that result from stresses generated when water in cracks and fissures expand on freezing.
Rocks at the earths surface are broken down by forces that result from stresses generated when rocks contract and expand on heating and cooling
What is biological weathering?
Breaking down of rocks caused by living things
What is a scree slope?
Bits of rock that have been broken apart from the bare rock on the bottom of the sides of mountains
What are different types of PHYSICAL WEATHERING?
Freeze-thaw, onion skin weathering
What are ways of biological weathering?
Animals dig through rocks to make burrows
Plants grow through rocks as they grow
What is chemical weathering?
Weathering of rock by acid rain
What is erosion?
The process where the surface of rocks are worn away by the transportation of material
What is weathering?
Breaking away of rock without moving
What is transportation?
The movement of rock from one place to another
What are different types of erosion?
Attrition - rocks knocking against each other, glacial erosion - plucking and abrasion, hydraulic action - when water
What is lava?
Molten rock that is released from the earths core in a volcano
What is magma?
Molten rock that is found within the Earth (in the mantle)
What is sediment?
Small fragments of rock and soil
Why don’t igneous rocks have any fossils?
The magma would have melted any fossils in the original rock
How are sedimentary rocks formed?
When sediment gets deposited after transportation to the bottom of the ocean. Overtime, more bits of rock fall on top and form layers. The weight and pressure of the rocks at the top compact the rocks at the bottom. The water is squeezed out from I between the layers causing the rocks to be cemented
What is deposition?
Sediment being deposited to from layers
What is compaction?
Sediment is squashed. Water is squeezed out
What is cementation?
Sediment grains are stuck together
Where would you find older grains on sedimentary rocks?
At the bottom
What are fossils?
A preserved skeleton or remains of an ancient loving thing
How are fossils formed?
Loving thing dies near a water source. It is buried and the flesh decays and only the bone is left. Sediment falls on top of the bone to form layers. It compresses the bone turning it into rock. Minerals soak through the bone to form a fossil. The rock is eroded away until the fossil is exposed on earths surface
How are metamorphic rocks formed?
Other rocks that have changed by immense heat and great pressure - they do not melt but the minerals they contain are chemically changed
How do igneous rocks change into sedimentary rocks?
They get weathered and eroded info small sediments and transported, deposited, compacted then cemented
How do sedimentary rocks change into metamorphic rocks?
Being at the bottom of the oven near the earths mantle, the heat from magma and the pressure of the sediment on top, can change the rock to metamorphic
How can metamorphic rocks change into igneous rocks?
They melt and become magma then cool solidify from volcanoes
What are the four parts of the earth?
Crust, mantle, outer core, inner core
What state of matter is the mantle?
Liduidy solid
What state of matter is the outer core?
Liquid
What state of matter is the inner core?
Solid
What happens to pieces of rock as they are transported by a river?
They get smaller and more rounded
What is the core made from?
Iron and nickel
What is the atmosphere?
The layer of gases that surround the earth
What do seismic waves do?
Identify earths layers
How do seismic waves identify earths layers?
The speed of seismic waves depends on density so we can use the travel time to identify changes in density with depth and show that earth is composed of several layers
What are primary waves like?
Refract at the boundaries, indicate that there are layers in the earth, trace through liquids and solids, fast
What are secondary waves like?
Slow, can’t travel through the outer core, indicates the outer core is liquid, travels through solids only
