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
What are the 5 processes of chemical weathering
Oxidation
carbonation
solution
hydrolysis
hydration
What is oxidation
When minerals react with oxygen often attacks sandstone
What is carbonation
When water falls and mixes with carbon dioxide to produce a weak carbonic acid. This reacts with calcium carbonate in rocks such as limestone
What is solution chemical wetahering
When salts in the rock are dissolved in water
What is hydrolysis
Chemical reaction between rock minerals and water. Granite reacts with water to create kaolin clay
What is hydration
Water molecules added to rock minerals so that they take up a larger space
What are the 2 processes of biological weathering
Tree roots
Organic acids
What is tree root weathing
Tree root s grow into cracks in the grounds and exert outward pressure - burrowing animals may have same effect
What is organic acid biological acid
Organic acids produced during decomposition of animal bodies and animal litter on shore platform molluscs secrete acids
What are the 3 mass movements
Rockfall
slumping
Landslides
What is rockfall
Rocks fall to foot of cliff
What is slumping
rock failure and movement along a curved rock plane leaving a crescent shaped scar
What is a Landslide
When rocks fall down a cliff staying in contact with the floor of the cliff throughout
What are the 5 wave processes
Abrasion
Attrition
Hydraulic action
Pounding
solution
What is attrition
Rock particles collide with each other
What is abrasion
Rock rubs against rocks
Hydraulic action
Occurs when waves break against a cliff face and water and air in cracks compress when the pressure is released the rocks jolt
What is pounding
Mass of water causes bits or rock to flake off 30 tonnes per metres squared can be expended by high energy waves
What are the 4 different types of transportation
Solution
suspension
saltation
traction
What is solution
minerals dissolved into mass of moving watery
what is suspension
Small particles of sand silt or clay that can be carried by currents
What is saltation
Saltation is when sediment that is to big to be carried in suspension is picked up and carried for a short distance before being dropped
What is traction
Traction is when the largest particles in the load are rolled across the sea/river bed
