Hydraulic Power: Waves crash against rock and compess the air in the cracks. Repeated compression will weden the cracks and makes bits of rock break away.
Abrasion: Eroded particles in the water scrape against the rock, removing small peices.
Attrition: Eroded particles in the water smash into each other and break into smaller fragments.
Solution: Weak carbonic acid in the seawater dissolves rock like Chalk and Limestone.
Mechanical Weathering is the breakdown of rock without changing its chemical composition, for example freeze thaw weathering:
- This happens when the temperature alternates above and below 0 degrees
- Water gets into the rock which has cracks
- When the water freezes it expands, putting pressure on the rock.
- When the water thaws it contracts, releasing the pressure from the rock.
- Repeating this process will widen the crack and cause the rock to break up
Chemical weathering is the breakdown of rock by changing its chemical composition. an example is Carbonation Weathering that happens in warm and wet conditions:
- Rainwater had carbon dioxide dissolved in it, which makes it a weak carbonic acid.
- Carbonic acid reacts with the rock that contains calcium carbonate.
Destructive waves, carry out erosional processes.
- High Frequency (10-14 waves per minute).
- High and steep.
- Backwash is more powerful than the swash.
- Material is removed from the coast
The main two factors that effect the size and power of the waves are:
- Wind- the force of the wind on the surface of the water
- Fetch- the distance of water over which the wind has blown to produce a wave.
Constructive waves deposit material to build up the land.
- Low frequency (6-8 waves per minutes)
- Low and Long
- The swash is more powerful than than the backwash, this carries material up the coast.
- These are made by weaker winds and have a shorter fetch than destructive waves