Sources Of Energy Flashcards

1
Q

What are the energy sources (4)

A

Wind
Waves
Tides
Currents

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2
Q

Where does wind move (2)

A

Air moves from areas of high atmospheric pressure to areas of low atmospheric pressure
Larger pressure gradient between two places = stronger wind

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3
Q

Waves in UK specifically (2+)

A

The prevailing (most usual) wind direction is from the south-west
Before reaching our coast = winds blown over the broad expanse of the Atlantic Ocean

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4
Q

What is the fetch

A

The distance wind travels over open water

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5
Q

What affects wave energy (3+)

A

Fetch
Strength of wind
Duration of wind

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6
Q

What is wind an agents of (2+)

A

Erosion = pick up and remove sediment from the coast and use it to erode other features
Moving sediment = it can pick up and move material

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7
Q

What agent does waves act as

A

Shaping the shoreline

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8
Q

Constructive waves what (5+)

A

Swash pushes more material from offshore up the beach than the backwash removes
Long wavelength
Low in height
Low in frequency
Deposition

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9
Q

Constructive wave beach look like (2+)

A

Gentle beach profile
Over time they will build up the beach and make it steeper

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10
Q

Destructive waves (5+)

A

Steep in height
Short in frequency
High in energy
Swash is short-lived and the backwash is forceful and takes material down the beach
Net effect = removal of beach material along the shoreline

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11
Q

Beaches and waves negative feedback (4+)

A

Constructive waves build up a beach
Beach profile steepens which can encourages destructive waves = remove material from the beach and deposit it offshore
Result = beach profile becoming less steep again = encouraging constructive to form
This will continue until a state of dynamic equilibrium is reached

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12
Q

Waves around a headland (4)

A

Tend to β€˜bend’ and have a higher frequency
Wave height steepness = erode
Waves approaching the headland meet shallower water first = friction with the sea floor
Slows headland-approaching waves and causes their frequency to increase

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13
Q

Waves around a bay (3+)

A

Waves spread out and become less frequent
Leads to a reduction in wave energy
Deposition

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14
Q

What is ave refraction (2+)

A

When waves approach a coastline that is indented they are refracted
Become increasingly parallel to the coastline

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15
Q

Overall impact of wave refraction (2)

A

Wave energy becomes concentrated on the headland
Presence of erosive features at headlands and deposition features in bays

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16
Q

Theory of wave refraction (2)

A

Continued erosion of the headland and deposition in the bays
State of equilibrium where the shape of the coastline remains static

17
Q

What does the term current refer to

A

The permanent or seasonal movement of surface water in the seas and oceans

18
Q

Type of currents (3)

A

Longshore
Rip
Upwelling

19
Q

What is a longshore current (3)

A

Occur because most waves approach the coastline at an angle
Result is a flow of water running parallel to the shoreline
Moves water and transports sediment parallel to the shoreline

20
Q

What is a rip current (3)

A

Strong localised underwater currents
Move water away from the shoreline
The fast-flowing offshore surge of water can be hazardous to swimmers

21
Q

How does a rip current form (2++)

A

When a series of plunging waves cause a temporary build-up of water at the top of the beach
Met with resistance from the breaking waves - the backwash is forced just below the surface following troughs in the beach profile

22
Q

What is an upwelling (3+)

A

Movement of cold water from deep in the ocean towards the surface
The dense cold water replaces warmer surface water = nutrient rich cold ocean currents
Form part of the pattern of global ocean circulation current

23
Q

What creates tides (2+)

A

Rise and fall in sea levels
Due to gravitational force of the moon, the sun and the rotation of the earth

24
Q

What does moon do to form tides (3+)

A

Pulls water towards it = high tide
There is a compensatory bulge on the opposite side of the Earth
In areas of the world between the two bulges = the tide is at its lowest

25
What is tidal range
The relative difference in height between high and low tides
26
What do tidal ranges determine
The upper and lower limits of erosion and deposition
27
What is spring tide (3+)
Twice a month = the sun, the moon and earth form a line Tidal force is at its maximum Total range is at its highest
28
What is the neap tide (3)
Sun and moon at 90Β° Solar tidal force cancels the moon gravitational force Tidal range + force at their minimum
29
Features of a high energy coastline (4)
Strong waves Strong prevailing winds Long fetch Rate of erosion bigger than deposition
30
Example of high energy coast in UK (2)
Cornwall North-west Scotland
31
Low energy coastline features (3)
Waves are less powerful Rate of deposition is greater than erosion Wave energy is low
32
Example of low energy coast in UK
Lincolnshire