physical processes Flashcards
what is a constructive wave
a constructive wave is a low energy wave that has a stronger swash than backwash. it is depositional and known as a spilling wave
what is a destructive wave
this is a higher energy wave with a stronger backwash than swash. it is often erosive of beach material and known as plunging.
what is a wave
this is an array of peaks and troughs formed by the friction of wind blowing on the sea’s surface.
what affects a waves size
How strong the wind is
How long the wind has been blowing
How big the fetch is
what is a waves fetch
the distance the wave/wind has been travelling for
what is weathering
this is when rock or coasts is eroded/worn away by factors of the weather and wildlife. It is wearing away rocks in situ.
what is chemical weathering
the breaking down of rocks through chemical changes happening within. it is common on limestone and chalk. one example is salt water may cause dissolving as it is slightly acidic.
what is mechanical weathering
the breaking up of rock without changing its chemical composition, purely eroding it through force.
what is biological weathering
this is when plants or living animals weaken rock by releasing acidic chemicals or by burrowing into cracks in the rock or roots expanding rock cracks.
what is mass movement
the downward fall of material under the force of gravity
name the types of mass movement
Rockfall
Landslide
Mudslide
Slump/Rotational shift
why does mass movement occur
it happens when rock or sediment of a cliff or coast is loosened by weathering, and it then becomes too saturated, heavy, or weak and gravity pulls it down to the ground
how does each mass movement occur
rock fall - the rock becomes weakened and breaks off from cliff, it falls
landslide - large section os rock slide down a cliff face in a straight line
mud slide - similar to a landslide but saturated soil flows down a cliff or slope
slumping - it’s when sediment falls down a hill at a curved angle
what is coastal erosion
erosion is the wearing away of the coast or rock by water and the sea
name the four erosion processes
solution
attrition
hydraulic action
abrasion
explain hydraulic action
this is when high power water forces into cracks in a rock, and traps air, eventually pressure forces it to crack the rock and this repeats over and over
explain attrition
this is when rocks in the sea knock with each other as it moves. it brakes up rocks into smaller pieces and smooths the edges
explain abrasion
this is when rocks in the sea are hurled at the cliff face by waves and the rocks grind and smash against the cliff
explain longshore drift
this is the process where sediment is transported along a beach when waves come in on the direction of the prevailing wind but the backwash moves back vertically in line with the beach, due to gravity. material is slowly moved along the beach by the sea.
explain why sediment is deposited in certain areas
sediment is deposited in areas where a wave reaches a low energy. this could be cue to a small fetch and weak wind, but it could also be due to a beach being a bay, or near an estuary, or due to coastal defences, which all combat wave force, by absorbing some energy.
