Geography Flashcards
What causes waves?
Waves are caused by the wind dragging on the surface of the water.
The length of water the wind blows over is called a fetch
What causes a wave to be large
- stronger the wind
- the longer it blows for
- and the longer the fetch
and the more energy they’ll have
What is swash
The waves at the shore they beak giving turbulent water called swash
What is Uprush?
The water rushing up the sand is called the uprush
Backwash?
The water rolling back is called the backwash another wave will arrive shortly
What happens when the backwash has more energy than the uprush
The waves eat at the land dragging pebbles and sand away ( this happens with high steep waves
What happens if the uprush has more energy then he backwash
Material is carried onto the land and left there ( this happens with low flat waves) the material builds up to builds up to make a beach
Why does the water level change
That’s mainly because of the moon as the moon travels around the earth it attracts the sea and pulls it upwards.
The Sun helps too but it is much further away o it’s pill is not so strong
When does high tide occur
High tides occur about every twelve and a half hours with low tides in between
What is the drop in sea level from high to low tide called
The tidal range
When does the tidal range happen
It changes through the year because the pull on the sea changes as the moon or is earth and earth orbits the Sun
What are tides caused by
Tides are caused by the moons gravity and the centripetal force of the moon orbits the sun
Types wave 3
Wind driven
Tidal
Tsunami
Destructive wave
A talk breaker it breaks down with great force
Taken beach away strong backwash
Weak swash
Constructive
Creates puts sand on the beach
Strong swash weak backwash
Smallest fetch =
Cause a small wave
Big fetch =
Big waves
What is prevailing wind
Wind that blows most often in the uk it is a south west wind
The waves at work? (1)
1) they wear away or erode the coast. These cliffs are being eroded some of the rock has already been weathered Broken down by the action for the weather and plants that make it easier to erode
The waves at work? (2)
They carry away or transport the eroded material
The waves at work? (3)
They drop or deposit it in sheltered areas where they lose energy
Erosion
They pound at the rock like a hammer over time this breaks the rock up
What is a hydraulic solution
They force water into cracks in the rock that helps to break it
Up
What is a solution
They dissolve soluble material from the rock
What is abrasion
The fling sand and pebbles against the rock these wear it away like sandpaper
What is attrition
The boys of rock that break off also get won down by knocking against each other
Shingle
They get smaller and smaller they end up as shingle which is pebbles and sand
What causes a fast erosion
The more energy the waves have and the softer the rock
Longshore drift
Hundreds of thousands of tones of pebbles and sand get moved along our coastline every year in this way
Groynes
Many seaside town build groynes of woods or concrete to stop their beaches being carried away by longshore drift
Deposition
Waves continually carry material on and off the land if they carry more on than off a beach forms
How does beach form
Beaches from in sheltered areas where the waves have less energy low flat waves carry material up the beach and leave it there some beaches are made of sand and some are shingle
What are 3 jobs they shape the coastline
They wear away or erode the coast
They carry away or transport the eroded material
They drop or deposit in the sheltered areas where they lose energy
Erosion
They pound at the rock like a hammer over time this breaks the rock up
Hydraulic action
They force water into cracks in the rock. That helps to break it up
Solution
They dissolve soluble material from the rock
Abrasion
They fling sand and pebbles against the rock these wear it away like sandpaper
Attrition
The bits of rock that break off also get worn down by knocking against each other
Shingle
They get smaller and smaller they end up as shingle and sand
Why do people build groynes
Many seaside towns build groynes of wood or concrete to stop their beaches being carried away by longshore drift
What is the process that makes a rock smooth
Abrasion
The stronger wind / wave
The bigger the erosion
Forming of a headland
Hard rock eroded more slowly than soft rock the result is a cliffs of hard rock
Wave - cut platform
The flat area at the base of these cliffs
Bay
Here the softer rock has been eroded away leaving a bay
Types of headlands
Cave arch and stack
Where is the eroded material carried to
Eroded material is carried along the coast by longshore drift
Beach
Some is deposited in sheltered area like this bay
Salt marsh
Here’s another headland but the longshore drift continues in its usual direction
Spit
So sand and shingle are deposited here in the sea and they build up a spit
Reasons for the usage of the beach
Leisure Fishing Wind power Porta Farming Industry Settlements Defende Dredging
Three factors to create a storm
Air pressure
High tides
Strong wind
Why could wave slash the promenade
Storm surge
Low air pressure
A air pressure is low the air is rising and the sea is pushed upwards
High tides
The high tides were at their highest during that time of the month
What causes a higher surge
The waves had more time to form stronger
What is coastal defense
Coastal defense yelp to protect the water flood or damage a place including erosion
Material of the cliffs help erode faster
If the cliffs are made of soft sand making it easier to get eroded
How does the rain effect destruction
The water first to the ground the material gets soaked meaning it will erode easier
Direction of cliff
If the cliffs are faced to a allow it to have a longer fetch the more damage more waves
What tyie of barrier would last the longest
Rock armiur
Caravan parks advantages
Caravan parks can be moved easily if there are in danger
Which types of defense is stop places from flooding
Sea walls
Defendes that reduce waves energy
Rock armour and artificial reef
How does the wave energy effect the erosion
The wave energy affects the erosion because it wont have as much power wont transport as much material s
