Constructive and destructive wavesPresentation Transcript
Lesson ObjectivesThis lesson is looking at the different types of wave you can get and how they effect the coast differently.By the end of the lesson you should be able to:Name the two types of waveDescribe the differences between themExplain how they change the coastline in different ways.
What is the definition of a coastline?
The coast – a narrow zone where land, sea and atmosphere meet
Swash and Backwash! Swash Backwash
Constructive Waves Swash Material deposited on beach Backwash
Destructive Waves Swash Material eroded off beach Backwash
Destructive waves mean steep, stepped beach caused by waves pulling sediment off the beachConstructive waves mean wide, flat and usually sandy beaches as waves deposit sediment on the beach
Constructive WavesDestructive Waves
Constructive and Destructive WavesConstructive Destructive• Height = Low (less than 1 • Height = High (more than 1 metre) metre)• Length = Long • Length = Short• Frequency = Fewer than 10 a • Frequency = More than 10 a minute minute• Energy = Low • Energy = High• Beach gradient = flat • Beach gradient = steep• Main process = deposition • Main process = erosion• Stronger swash • Stronger backwash
Key WordsFetch – the distance a wave has travelledSwash – the forward movement of a wave up the beach after the wave has brokenBackwash – water from a breaking wave which flows under gravity down the beachConstructive Wave – deposits sediment, building up the beachDestructive Wave – a wave that removes sediment from the beach, eroding it.