systems Flashcards
What is a system
A system is a set of interrelated objects containing stores and processes that are connected to form a working unit
What are the components of open systems
Inputs - could include kinetic energy from wind thermal energy from sun potential energy from deposition, mass movement and weathering from cliffs
Outputs- include marine and wind erosion as well as evaporation
Flows- like longshore drift
What is it called when a systems input equal a systems output
The system is in equilibrium. When equilibrium is disturbed the system will change to restore equilibrium - known as dynamic equilibrium
What is a sediment cell
Stretch of coastline where the movement of course sediment sand and shingle it is a closed system
How many sediment cells are there around the UK
11
What large physical feature blocks the movement of sediment
Lands end
What makes a wave more powerful
Fetch(distance wave has travelled over )
Bathymetry
How do waves travel
waves are the movement of energy not water molecules Gravitational potential energy from the waves crest and kintetic energy from the movement of water molecules. Water molecules move in circular motions to create waves. Tis also creates ripples in the sand
Do storm waves have a high or short wavelength
Storm waves typically have a short wavelength whilst swell waves have a high wavelength typically up to 20 second. Storm waves have a greater height
How do waves break
At a depth of half a wavelength there is friction between the deepest water molecules and the sea bed. This causes the waves to bunch up and the top of the wave to go faster than the bottom causing the wave to topple
What is a spilling wave
Steep waves breaking into gently sloping beaches
What is a plunging wave
Moderately steep waves breaking onto steep beaches the water plunges vertically downwards
what is a surging wave
Low- angle waves breaking onto steep beaches
Differences between destructive and constructive waves
Destructive waves have greater height, shorter wavelengths and a higher frequency often 12-14 waves per minute The swash is weaker than the backswash
How are tides produced
Tides are produced by the gravitational pull of the moon and to a lesser extent the sun. Where the moon is there is a bulge in water this is called a neap tide. The highest tides spring tides are when the sun and moon align
How does lithology affect coastlines
Some rock types like clay have weak lithology with little resistance to erosion mass movement and weathering. Basalt however is made of dense interlocking crystals that make it more resistant to erosion and weathering
How does the geological structure affect coastlines
Structural concerns such as jointing, bedding and faulting. In porous rocks such as chalk separate the mineral particles. These pores absorb and store water
How do currents affect the coastline
Rip currents transport sediment caused by tidal motion or waves breaking at right angles to coast. Rip currents can cause cusps. Warm ocean currents transport warm water
How do rivers affect coastlines
Rivers deposit sediment on the coast 80 percent of sediment comes from rivers
What are the 4 types of mechanical weathering
Freeze thaw
pressure release
thermal expansion
salt crystallisation
What is freeze thaw
Water enters cracks and joints freezes and expands dislodging rocks
What is pressure-release
Overlapping rocks are removed by weathering and erosion so the underlying rock expands and fractures
What is thermal expansion
When rocks are expanded when they are heated and contract when cooled this can flake off bits of rock
What is salt crystallisation
Solutions of salt water can seep into pore spaces in the rock then recrystallise and expand the rock causing bits of it to fall off
