Shaping Coastlines
Name two natural factors that can shape a coastline.
Any two of: waves, currents, weather patterns, tectonic plate movement, sea-level change, climate change or sediment movement.
What is fetch?
The distance over which wind blows across the surface of the water.
Define longshore drift.
The movement of sediment along a coastline as waves approach the shore at an angle.
Identify two atmospheric factors that influence ocean conditions.
Any two of: air temperature, wind speed, wind direction, rainfall or barometric pressure.
What is wave reflection?
Wave reflection occurs when a wave hits a surface and is redirected back into the water.
What is coastal erosion?
The removal of rock, sand or sediment from a coastline.
Identify the main force responsible for producing tides.
DOUBLE POINTS
The gravitational pull of the Moon, with a smaller influence from the Sun.
Define the term sand budget.
The balance between the amount of sand entering and leaving a coastal system.
Explain how wind transfers energy to the ocean.
Friction between the wind and the water transfers energy to the ocean surface, producing waves and surface currents.
What is wave refraction?
Wave refraction is the bending of waves as different sections of a wave slow at different rates in shallow water.
What is coastal accretion?
The accumulation of sand or sediment along a coastline.
Explain how fetch influences wave size.
A longer fetch allows wind to transfer more energy to the water, generally producing larger waves.
Describe how waves move sand through longshore drift.
Swash carries sand diagonally up the beach, while backwash pulls it directly downslope, gradually moving sand along the coastline.
Explain how differences in land and ocean temperatures can produce a sea breeze.
During the day, land heats faster than the ocean. Warm air rises over the land, and cooler air moves inland from the ocean to replace it.
What is wave diffraction?
Wave diffraction is the spreading or bending of wave energy around an obstacle or through an opening.
Explain how rising sea levels can change a coastline.
DOUBLE POINTS
Rising sea levels allow waves and currents to act farther inland, increasing erosion, coastal flooding and shoreline retreat.
Explain what happens to wave speed as a wave enters shallow water.
The wave slows because it begins interacting with the seafloor. Its wavelength decreases, its height increases and it may eventually break.
Explain the difference between a positive and negative sand budget.
A positive sand budget occurs when more sand enters than leaves, causing accretion. A negative sand budget occurs when more sand leaves than enters, causing erosion.
How can falling barometric pressure indicate changing coastal weather conditions?
Falling pressure can indicate an approaching low-pressure system, which may bring stronger winds, increased cloud, rainfall and larger waves.
Compare wave reflection and diffraction.
Reflection redirects waves away from a surface, whereas diffraction spreads wave energy around an obstacle or through an opening.
A beach becomes narrower after several days of strong winds and large waves. Explain the likely cause of this change.
Strong winds produced larger waves that removed more sediment than they deposited, creating a negative sand budget and causing erosion.
Explain how current strength, gravitational pull and wave action can combine to influence tidal movement near a coastline.
Gravitational pull generates the tides, while currents transport tidal water and waves modify water movement as it approaches and interacts with the shore.
A groyne traps sand on one side but causes the beach on the opposite side to become narrower. Explain why.
DOUBLE POINTS
The groyne interrupts longshore drift. Sand accumulates on the updrift side, while the downdrift beach receives less replacement sand and experiences erosion.
Explain how warm ocean water can influence coastal weather and wave conditions during a tropical storm.
Warm water supplies heat and moisture to the atmosphere, which can strengthen the storm. Stronger winds then transfer more energy to the ocean, creating larger waves and greater coastal erosion.
Waves approach a coastline containing a headland, a sheltered bay and a harbour wall. Explain how refraction, diffraction and reflection could affect the coastline.
Refraction concentrates wave energy around the headland and disperses it in the bay. Diffraction spreads waves around the harbour wall, while reflection redirects wave energy from the wall and may create interference patterns.