The Changing Earth🌏🌍🌎

Question 1

What is an igneous rock and how is it formed? Give an example.

Answer 1

Rocks formed from cooling magma/lava.

Eg: Basalt, Obsidian, granite

Question 2

What is a metamorphic rock? Give an example.

Answer 2

A sedimentary or igneous rock gone through additional heat/pressure.
Eg: Quartzite, marble, slate.

Question 3

What is the Inner Core made out of? And what is the temperature?

Answer 3

Iron and nickel. It is a solid due to the immense pressure. It is roughly 7000C. It is 2400km thick.

Question 4

What is the Outer Core made out of and how hot is it? What is its thickness?

Answer 4

It is made out of molten iron and nickel, it is mostly liquid and is roughly 4000-6000C. It is 2300km thick.

Question 5

What is the mantle made up of? What is the temperature and what is the thickness?

Answer 5

Molten rock, 500-2000C is in a liquid state and s 2900km thick.

Question 6

What is the Crust made out of and how thick is it?

Answer 6

It is made out of rocky material and is 40+km thick. It is a solid.

Question 7

How do scientists know the different layers of the Earth and what state they are in?

Answer 7

Scientists use earthquakes which cause a seismic wave, these waves travel through the earth and get refracted or bent when it hits a new layer. We know the density because the speed of the waves change the denser the layer gets.

Question 8

Name the three seismic waves.

Answer 8

• Primary (P wave)
• Secondary (S wave)
• Surface Waves

Question 9

Name the characteristics of each seismic wave.

Answer 9

• P waves: Fast moving compression wave like a sound wave in air.
• S waves: Ripple like lateral movement of the ground, relative to the direction of travel. Slower than p waves
• Surface waves: while other waves go through the earth, surface waves do not.

Question 10

What is an epicentre of an earthquake.

Answer 10

The start point of an earthquake.

Question 11

Describe weathering.

Answer 11

Breaking up of rocks.

Question 12

What is physical weathering

Answer 12

Tree roots, ice, wind, water, rain

Question 13

Chemical weathering

Answer 13

Acid

Question 14

Describe erosion.

Answer 14

Removal of weathered material.

Question 15

What is an agent?

Answer 15

What causes rocks to be weathered and eroded

Question 16

What is the difference between intrusive rocks and extrusive rocks?

Answer 16

Intrusive rocks formed under the earths crust

Extrusive rocks formed on top of the earths crust

Question 17

How does this affect crystal sizes in rocks?

Answer 17

Intrusive rocks have larger crystals because the rock cools slower and giving more time for crystals to form.
Extrusive rocks cool quickly so crystals have less time to cool.

Question 18

Give examples of intrusive and extrusive rocks

Answer 18

Intrusive: granite, diorite, slate
Extrusive: Basalt, obsidian, porphry

Question 19

Why is coal and limestone named an organic rock?

Answer 19

Coal and limestone are made from living lifeforms.

Question 20

What is a sedimentary rock and how is it formed? Give an example.

Answer 20

Rocks formed from sediments deposited by water, wind or ice. The sediments are cemented together in layers, under pressure.
Eg: Conglomerate, sandstone, siltstone

Question 21

Describe lustre

Answer 21

How it reflects light from its cut surface. Might be described as dull,metallic, pearlescent or glassy.

Question 22

Describe streak.

Answer 22

Is the colour and texture of the mark that the mineral leaves behind when its scratched across over a hard white surface.

Question 23

What is the lithosphere?

Answer 23

Rigid outer part of the crust, consisting of the crust and upper mantle