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