river physical processes 1 ✓

Question 1

what is weathering ?

Answer 1

the breaking down of rocks, soil, and minerals

Question 2

how does biological weathering work (roots and burrow nesting) ?

Answer 2

• plant roots can get into small cracks in the rocks
• as the roots grow the cracks become larger
• this causes small pieces of rock to break away

Question 3

how does chemical weathering work (acid rain) ?

Answer 3

• caused by a chemical reaction
• when chemicals like sulphur dioxide and nitrogen oxides are released into the air
• they react with substances like water oxygen or other chemicals to form acid pollutants
• when it rains the acid rain falls onto the rocks and erodes them away

Question 4

how does mechanical weathering work (freeze thaw) ?

Answer 4

• water enters cracks in rock
• when temperatures drop the water freezes and expands causing the cracks to expand
• as the temperature increases the ice melts and makes its way deeper into the cracks
• the process repeats itself until the rock splits entirely

Question 5

what is mass movement ?

Answer 5

downhill movement of sediment that moves because of gravity

Question 6

what is slumping (mass movement) ?

Answer 6

saturated soil slumps down a curved surface

Question 7

what is sliding (mass movement) ?

Answer 7

large blocks of rocks and soil slides down the hill

Question 8

what is soil creep (mass movement) ?

Answer 8

slow downward progression of rock and soil down a low grade slope

Question 9

what is erosion ?

Answer 9

process by which the surface of the Earth gets worn down

Question 10

what is corrosion/abrasion (erosion) ?

Answer 10

process of rocks and pebbles carried by the waves wearing away rocks as they are thrown against cliffs

Question 11

what is saltation (transportation) ?

Answer 11

pebbles are bounced along the river bed

Question 12

what is hydraulic action (erosion) ?

Answer 12

air becomes trapped in the cracks of the river bank and bed, and causes the rock to break apart

Question 13

what is solution (erosion) ?

Answer 13

• this is the chemical action of sea water
• the acids in the salt water slowly dissolve rocks on the coast
• limestone and chalk are particularly prone to this process

Question 14

what is transportation ?

Answer 14

river picks up sediment and carries it downstream

Question 15

what is deposition ?

Answer 15

when the sea loses energy, it drops the material it has been carrying

Question 16

what causes deposition to happen ?

Answer 16

when the flow of water loses energy and does not have enough energy to carry the material anymore

Question 17

what is attrition (erosion) ?

Answer 17

when rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded

Question 18

what is traction (transportation) ?

Answer 18

• large, heavy pebbles are rolled along the river bed

- common near the source of a river

Question 19

what is solution (transportation) ?

Answer 19

the transport of dissolved chemicals

Question 20

what is suspension (transportation) ?

Answer 20

lighter sediment is suspended within the water, most commonly near the mouth of the river

Question 21

how does longshore drift work (transportation) ?

Answer 21

• prevailing wind blows
• waves carrying sediment into the beach at an angle
• waves break on the shore
• water runs back into the sea it carries the sediment back down the beach, perpendicular to the angle of the shoreline under the influence of gravity
• results in a zigzag motion as sediment is transported along the coastline
• process means that over time beaches can change shape