The Physical Geography of the UK Flashcards
What is the relief ?
The shape of the land .
What causes waves
-Waves are caused by wind blowing over the sea (friction) .
What is the crest ?
The top of a wave
What is a trough ?
The base of a wave
What is the wave height ?
Vertical distance from trough to crest .
What is the wave length ?
The vertical distance between two successive crests .
What is the wave frequency ?
The number of waves breaking per minute .
What is the fetch ?
The distance over which the wind ahs blown .
-How far the wave has stretched .
What is the swash ?
Movement of water up the beach .
What is backwash ?
Movement of water down the beach .
What does the strength of a wave depend on ?
-The speed of the wind ; strong wind s result in stronger waves because more energy is transferred intoo waves .
What does the strength of a wave depend on (2) ?
-How long the wind has been blowing , the longer the wind has been blowing , rhw more energy is transgerred and the stronger the waves .
What does the strength of a wave depend on (3) ?
-The fetch , the longer the fetch , the greater is the possibiliry of large waves if the storms are widespread.
Formation of a shallow wave in water .
- In deep water , each water molecule moves within a circular motion .
- As a wave moves into shallower water , they begin to stack up .
- Waves slow down due to friction with sea bed , and increase in height .
- Water moelecules now move in elliptical shape (oval)
- Frictional drag increases clsoer to beach so bottom of wave slows down so top part of wave is travelling faster , casuing wave to tilt , break and move towards shore in surf zone .
- As wave breaks and flows onto the beach , swash and gravity takes i down beach as backwash .
What are some characteristics of constructive waves ?
- Constructive waves are found in sheltered bays and spits , where they build up sandy beaches .
- Are low energy
- Long wave elngth so low frequency 8-10 per min
- only gains little height when breaking a water spreads long way up gently sloping beach .
- Strong swash and very weak backwash .
How is it possible to build beach with contructive waves .
Strong swash means a lot of sediment can be deposited and weak backwash so cannot be broguht back into sea .
How is it possible to build a beach with destructive ways ?
-Found in pebble beaches ,
-common winter than summer .
Short wave length so hgih frequency 10-14/m
-Wave height 1 m gains much height .
-Plunges on to a steep beach but dosent travel far up .
-Restricted swash but very strong backwash .
How do destructive ways drag material out to sea ?
-Stronger backwash than swash drags beach material out to sea eroding the beach .
Similarity betwene constructive and destructive waves .
-Both waves are fromed by wind blwoign over the surface of th sea and have a swash and backwash .
What is weathering ?
The breakup of material like rock on site .
What is erosion ?
Erosion is the break up of material like rock along some sort of transport process (landslide)
What is mechanical weathering ?
Mechanicl weathering is a physical processes take place to break apart large rocks into smaller ones .
Example freeze thaw .
Explain freeze thaw mechanical weathering :
-Water settles between cracks in a cliff and then turns into ice which naturally has a larger volume than water .
As a result , the rock is slightly displaced outwars , hwoever , when the ice melts , the water travels further down the crack and then expands agin ,t his cyle of weathering continues until rock fully splits .
What is salt weatherig , mechanical weathering ?
whenn salt spray from sea gets into a rock , evaporates and crystalises , putting pressure on the surroudnign rock ,weakening its strucutre .
What is Biological weathering ?
Biological weathering is to do with how organisms physically alter the environemnt .
- E.g rabbits dig hoels which break apart soil and begetation like treesbreak up under soil undenreath .
- Seen in old roads , tarmac lifted by tree roots .
What is chemical weathering ?
-In chemical weathering, the chemical composition of rock changes.
CARBONATION
-When the climate is warm and wet, carbon dioxide can dissolve in rain to create a ‘carbonic acid’.
-The carbonic acid in rainfall hits rocks and dissolves the parts of the rock made of calcium carbonate.
-Warm wet conditions btw This also breaks down rock.
What is mass movement ?
Mass movement describes the large movement of soil and rock down the slope of a hill or cliff.
Causes of mass movement ?
- Mass movements are caused by weathering, erosion, and gravity.
- Small changes over time can mean that the centre of gravity of a cliff can hang over the sea, instead of over land making the cliff unstable and prone to mass movement.
Types of mass movement
- rockfall
- slides
- slumps
What are rock falls ?
Rockfalls are when the cliff (materials) break and crumble down the cliff down a slope .
What are landlsides ?
Slides are when material moves down a slope in a straight line.
What are slumps ?
- Slumps are when material moves down a slope at a curve .
- Slump is a slip plane under the land is formed . The cliff slumps down in layers .
What are the different type of erosions ?
- Hydraulic Power .
- Atrrition
- Solution
- Abrasion
What is hydraulic power ?
Hydraulic power is where the force of waves hits against a cliff face and causes rock to break off.
What is attrition ?
- Attrition is where different bits of material carried by waves in seawater hit against each other.
- This causes them to break apart but also become smaller and more rounded.
What is solution ?
Solution is where weak acids in seawater dissolve soluble rocks like chalk and limestone .
What is abrasion ?
-Abrasion is where pieces of material are picked up by waves and hit or scrape against the sea bed or the side of a cliff.
This wears away the sea bed or cliff because the material acts like sandpaper.
What is a wave-cut platform ?
a wave-clut platform is when cliffs are eroded by destructive waves, resulting in the formation of wave-cut platforms.
Stage 1 of a wave-cut platoform ?.
Destructive waves are responsible for most of the erosion at the base of cliffs.
- Hydraulic action and abrasion wear away the base of the cliff around the high tide mark.
- Eventually, this erosion causes a wave-cut notch to form.