Chapter 14

Question 1

What is weathering?

Answer 1

the process of breaking down rock and minerals. Weathering is caused by Sun’s energy, wind, running water, ice, chemical reactions, and the actions of organisms.

Question 2

What is the difference between young mountains and old mountains?

Answer 2

Young= sharp peaks, no vegetation at the peaks.
Old= round peaks, not that tall, and there is vegetation.

Question 3

What is mechanical weathering?

Answer 3

the process of breaking down rocks and minerals into smaller pieces by physical force. Also called physical weathering.

Question 4

What is chemical weathering?

Answer 4

the process of breaking down rocks and minerals by chemical reactions.

Question 5

What two main sources of energy cause weathering?

Answer 5

the Sun and Earth’s internal energy.

Question 6

What is the difference between the Sun and Earth’s internal energy?

Answer 6

The Sun= drives our weather and the water cycle.

Earth’s internal energy= results in the movement of lithospheric plates on Earth’s surface.

Question 7

How is gravity important in weathering?

Answer 7

important process because gravity causes water and pieces of rock to move downhill.

Question 8

What is frost wedging?

Answer 8

mechanical weathering that results from freezing water.

Question 9

Where does frost wedging occur?

Answer 9

occurs in areas with available water and temperatures that fluctuate around the freezing point.

Question 10

What is biological weathering?

Answer 10

Weathering by plants and animals.

Question 11

When does mechanical weathering happen?

Answer 11

weathering by plants occurs when roots grow into cracks in a rock.

Question 12

What is root wedging?

Answer 12

roots exert force on the rock as they grow and may cause the rock to split.

Question 13

How do animals cause weathering?

Answer 13

Animals cause mechanical weathering when they dig into soil or burrow underground.

Question 14

What is exfoliation?

Answer 14

Exfoliation is a weathering process that results in rock layers peeling away. Outer layers peel away first, and then the layers underneath expand and get weathered themselves.

Question 15

How does wind cause weathering?

Answer 15

Sand gets blown around in the wind and chips away tiny bits of rock from the surface of exposed rock.

Question 16

What is a hoodoo?

Answer 16

A hoodoo is a tall pillar that forms when wind weathers down large rocks. (See page 329 for a picture in the bottom right corner of the page)

Question 17

What causes chemical weathering? (4 things)

Answer 17

• water and minerals
• acid rain
• oxygen in the atmosphere
• weathering by plants

Question 18

How can water and minerals cause chemical weathering?

Answer 18

water can react with minerals in the rock and cause chemical changes. (example: feldspar reacts with water to make clay)

Question 19

How does acid rain cause chemical weathering?

Answer 19

Acid rain happens when pollutants in the atmosphere mix with water and form an acidic solution. That acidic solution comes down as rain and weathers rock.

Question 20

How does oxygen in the atmosphere cause chemical weathering?

Answer 20

Oxygen in the atmosphere changes metals in minerals through a process called oxidation. Example: oxygen combines with iron to make rust.

Question 21

How can plants cause chemical weathering?

Answer 21

Moss and other plants can cause chemical weathering because they release chemicals that cause the rock to break down.

Question 22

Can chemical and mechanical weathering happen at the same time or do they have to happen separately?

Answer 22

They can happen at the same time.

Question 23

What factors affect the rate of weathering? Give reasons/examples

Answer 23

1) weather and climate. Ex: rocks weather faster in warm, humid climates. The weather slower in dry, cold climates.
2) Plants and enimals. Ex: plants growing or animals digging can change how much of a rock is exposed to weathering
3) minerals. The kind of minerals on a rock changes how fast the rock weathers. Ex: marble weathers faster than grainte.
4) Surface area. More exposed surface area –> weathers faster.

Question 24

What is erosion?

Answer 24

the process of moving sediment by wind, water, ice, or gravity

Question 25

What moves sediment?

Answer 25

running water, wind, ice

Question 26

How does sediment usually move?

Answer 26

downhill because of gravity

Question 27

How does running water move sediment?

Answer 27

when water/wind/ice moves sediment, “depositing” it (i.e. putting it somewhere) is called deposition

Question 28

What affects how water moves sediment?

Answer 28

• volume of water (lots of water moves sediment really easily; a little water moves just a bit)
• slope (steep slopes –> lots of erosion compared to shallow slopes.) p. 334 for picture
• rockiness: rocky landscapes can trap sediment, so less erosion happens

Question 29

What sorts sediment? How?

Answer 29

Water sorts sediment.

When running water slows down (example: River flowing into the sea), the largest particles being carried settle to the bottom first. Then the middle particles settle. Finally, the smallest particles settle. (see page 335 for picture)

We call this a graded bedding. The sediment is ordered with the largest particles on the bottom, then medium, and finally smallest on top.

Question 30

What is the direction of younging?

Answer 30

the direction of the younger layers of sediment. remember: youngest/finest particles are on top, oldest/largest particles are on bottom.

Question 31

How does ice move sediment?

Answer 31

Glaciers can slide around without breaking; as they slide around in a mountain valley (see page 337 for picture), they drag rock/sediment with them.

Question 32

How does gravity move sediment

define mass wasting, landslide, rockfall, mudflow

Answer 32

• -Mass wasting - the downhill movement of large amounts of rock and sediment because of gravity.
• -Landslides - when large mass of soil or rock slides down a steep slope
• -Rockfall - a big chunk of rock is split off of a large landform due to weathering
• -mudflow - an event that occurs when a large amount of rock and water flow down a mountain

Question 33

What is slumping?

Answer 33

when soil particles become surrounded by water so that the ground slides or slumps. See 340 for pictures.

Question 34

How do people cause erosion?

Answer 34

–when humans use the land and build on it, they can cause erosion: farmers removed topsoil and grass, so the earth got very dusty.

Question 35

How do rivers shape land?

Answer 35

• they form river valleys

- river valleys tend to be v-shaped

Question 36

What is a floodplain?

Answer 36

a flat land alongside a river that tends to get flooded.

Question 37

What is a meander?

Answer 37

an s-shaped curve that forms in some rivers: picture on page 344