Coasts

Beaches are accumulations of sand or pebbles deposited by waves in sheltered areas. Bays are curved indentations in the coastline formed where soft rock is eroded more quickly than harder rock on either side.

Sea cliffs are steep rock faces at the coast formed by wave erosion undercutting the land. Headlands are promontories of harder rock that jut out into the sea. Both are high-energy erosional features found on exposed coastlines.

Coastal erosion is the wearing away of the land by the sea. Waves use hydraulic action, abrasion, attrition, and solution to gradually break down cliffs, headlands, and beaches, reshaping coastlines over time.

Sand dunes are hills made of sand, found on beaches and deserts. They form when wind carries sand and deposits it, and are stabilised by plants whose roots bind the sand together. Dunes form an important coastal ecosystem.

Waves are formed by the transfer of energy from wind to water. The size of a wave depends on wind speed, duration, and the distance of open water the wind crosses (fetch). Constructive waves build up beaches; destructive waves erode them.