Understanding Coastal Processes: Abrasion, Attrition, Hydraulic Action, and Solution, Lecture notes of Physics

Download Understanding Coastal Processes: Abrasion, Attrition, Hydraulic Action, and Solution and more Lecture notes Physics in PDF only on Docsity! Define the key terms: - Abrasion - Attrition - Hydraulic action - Solution Y11 Coasts Abrasion – caused by waves picking up material which is forced against the cliff face wearing it away Attrition – where stones and pebbles in the sea knock against each other causing them to become smoother and rounded. Hydraulic action – the force of the water causes the land to wear away Solution – soluble particles in the rock are dissolved. This weakens the structure of the rock and over time causes the land to wear away. Define the key terms: a. Fetch b. Backwash c. Swash Y11 Coasts Fetch – The distance over which wind has blown to form a wave Backwash – the movement of water back down a beach Swash – the movement of water up a beach Describe and explain the way in which waves form Y11 Coasts - Wind blows over surface of water – creates friction - Frictional drag causes water particles to begin to rotate and energy is transferred forward in the form of a wave - as a wave reaches shallow water, friction between the sea bed and the base of the wave – causes the wave to slow down – shape becomes more elliptical - top of the wave however – unaffected by the friction – becomes steeper – eventually breaks - when it breaks – water moving up the beach in the swash and the water moving back down the beach in the backwash. Outline the main characteristics of constructive waves Y11 Coasts - Low <1m - Low energy - Low frequency (<10/min) - Swash>Backwash - Deposition - Outline the main characteristics of destructive waves Y11 Coasts - High (>1m) - High energy - High Frequency (>10 min) - Swash<Backwash - Erosion Describe 3 factors which will affect the strength of a wave Y11 Coasts Strength and speed of wind – faster the wind – more energy transferred – bigger wave produced Duration of the wind – length of time for which the wind has blown – longer the wind blows for, the more energy is transferred to the wave. Fetch – the distance over which the wind has blown (i.e. how far the wave has travelled) – longer the fetch the stronger the wave. Outline a form of physical weathering operating at the coast Y11 Coasts Frost Shattering – water gets into cracks in the rocks – if temperatures fall below freezing at night the water freezes and expands (9-10%); puts pressure on the rock around – then thaws. Freeze-thaw cycle gradually forces the rock apart. Salt crystal growth – sea water contains salt from spray from the waves – when evaporates leave salt behind – salt crystals growing in the cracks in the rock can force the rocks apart Outline the mass movement processes of (i) slumping and (ii) soil creep Y11 Coasts Slumping – erosion at base of cliff may lead to rotational slipping of cliff above – particularly on clay cliffs – during dry periods the clay contracts and cracks and will become saturated during wet periods – moving downslope due to gravity. Soil Creep – slow downhill movement of soil Name 4 examples of erosion landforms at the coast Y11 Coasts - Headlands and Bays - Wave Cut Platform - Cliff - Cave - Stack and Stump - Arch Name 3 examples of deposition landforms at the coast Y11 Coasts - Beaches - Spits - Bars