Earth - Science

Question 1

Geology Definition

Answer 1

Geology is a branch (or specific area) of science that studies rocks. People who study geology are called geologists

Question 2

4 Layers of Earth

Answer 2

Crust
Mantle
Outer Core
Inner Core

Question 3

Crust - (located where/thickness/made of/other features)

Answer 3

Outermost layer of rock found on Earth.

• Earth’s Surface
• 30 Km Thick
• Top layer of crust - Lithosphere
• Bottom layer of crust - Asthenosphere

Question 4

Mantle - (located where/thickness/made of/other features)

Answer 4

Layer of rock below the crust

• Made up of solid & liquid rock
• Thickest layer (3000 Km)
• Very hot & constantly moving

Question 5

Outer Core - (located where/thickness/made of/other features)

Answer 5

Layer of rock outside the inner core.

• Hottest layer
• Made of molten rock
• Thickness of 2000 Km

Question 6

Inner Core - (located where/thickness/made of/other features)

Answer 6

Innermost layer of solid rock on Earth

• Made of solid iron and nickel.
• Thickness of 1000 Km

Question 7

5 things that help scientists identify rocks

Answer 7

Colour
Hardness
Lustre
Streak
Cleavage

Question 8

Colour

Answer 8

Different minerals which make up a rock give them their colours and patterns

Question 9

Hardness

Answer 9

The property of a substance to resist scratching or denting

Question 10

Lustre

Answer 10

This is how shiny a mineral is. We describe lustre with terms like metallic (like a shiny coin), and earthy (like dirt).

Question 11

Streak

Answer 11

This is the colour of the mineral when crushed into a powder, or when the mineral is scratched against a tile. Often the colour of the streak is different from the main colour of the mineral.

Question 12

Cleavage

Answer 12

The way a crystal naturally breaks along a line

Question 13

Igneous Rock Definition

Answer 13

Igneous rocks are rocks which are formed by the solidification of magma or lava

Question 14

Magma Definition

Answer 14

Magma is hot molten rock located below the Earth’s surface (in the mantle)

Question 15

Lava Definition

Answer 15

Lava is hot molten rock that is above the surface

Question 16

Extrusive Igneous Rock Definition

Answer 16

Extrusive Igneous Rocks form by the cooling of lava (magma that has reached the Earth’s surface). Lava on the Earth’s surface cools rapidly (very quickly) so they have small to microscopic crystals. Examples include Obsidian, Pumice and Basalt

Question 17

Intrusive Igneous Rock Definition

Answer 17

Intrusive Igneous Rocks form by the cooling of magma below the surface of the earth. Lava below the surface of the Earth cools slowly, so they have large crystals, which can be seen without a magnifying glass or microscope.. Examples include Granite and Dolerite.

Question 18

Why are some igneous rocks light coloured while others are dark coloured

Answer 18

Dark igneous rocks have a high content of heavy metals like Iron in them (e.g. Basalt and Dolerite), whilst light igneous rocks have more lighter elements like silicon, aluminium and oxygen (e.g. Granite).

Question 19

Porous rocks (how do porous igneous rocks form) - (extrusive or intrusive)

Answer 19

Porous igneous rocks have a large number of air spaces in them (e.g. pumice) due to gas bubbles that were trapped in the rock when The lava was rapidly cooling. Porous igneous rocks are always extrusive igneous rocks.

Question 20

How do metamorphic rocks form?

Answer 20

Metamorphic rocks form when existing rocks of any type are modified when they are subjected to high temperature and pressure.

Question 21

Contact Metamorphism Definition

Answer 21

Contact metamorphism occurs in rocks that come in contact with hot magma as it pushes through the mantle and crust. It occurs in particular local places on a much smaller area than regional metamorphism.

Question 22

Regional Metamorphism Definition

Answer 22

Regional Metamorphism occurs over a wide are in rocks that are buried deep beneath the Earth’s surface are exposed to very high pressure and temperature. It also happens to rocks which are on tectonic plate boundaries are exposed to heat and pressure when these plates collide

Question 23

Recrystallisation Definition

Answer 23

Heat and pressure can melt rock causing a process called recrystallisation to occur. When the rock is molten the elements can move around, and new minerals form in this process. Recrystallisation occurs when new crystals grow as the rock cools down.

Question 24

Foliation Definition

Answer 24

Another metamorphic change is in the texture of the rock called foliation, where the minerals in these rocks become squashed into layers. Pressure causes the minerals to become squashed flat or form into long needle shapes. The rock then develops layers or bands in a process called foliation.

Question 25

Sedimentary Rocks (how is it formed) (made of)

Answer 25

Sedimentary rocks are a type of rock formed by the compaction and cementing together of sediments. Sediments are mostly made up of particles of other rocks (such as mud, sand, and pebbles) that have been washed into riverbeds, lakes, or the sea.

Question 26

Clastic Sedimentary Rocks

Answer 26

Clastic sedimentary rocks form from weathered rock sediments.

• The sediments are cemented together
• Sometimes find fossilised remains of long-dead organisms in them.

Question 27

Chemical Sedimentary Rocks

Answer 27

Chemical sedimentary rocks form when materials dissolved in water come out of solution, form a solid, and sink to the bottom. It is rare to see any layering or fossils in chemical sedimentary rocks.

Question 28

Organic Sedimentary Rocks

Answer 28

Organic sedimentary rocks are formed by dead animal or plant material. Organic sedimentary rocks can be layered, depending on the way in which the fossils and sediments are deposited.