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Geography Chapter 12
The sea: how it shapes our coast
| Question | Answer |
|---|---|
| How are waves formed? | Formed when wind moves across the surface of the sea |
| What is a fetch? | The distance of open sea over which wind blows |
| What is swash? | The water that rushes up a beach when a wave breaks |
| What is backwash? | The water that returns back down the beach |
| What is a constructive wave? | When the swash is greater than the backwash and material is deposited on the beach |
| What is a destructive wave? | When the backwash is greater than the swash and material is eroded and carried away |
| What is hydraulic action? | Physical force of the waves breaking material off the coastline |
| What is abrasion? | Any loose material (rocks and sand) is thrown by the waves against the coast and breaks off material |
| What is compressed air? | When waves crash against a cliff, air gets trapped in the cracks and becomes compressed. When the waves retreat, the pressure is suddenly released and shatters the rock |
| What is solution? | Some rocks are dissolved by water |
| What is attrition? | Stones that are carried in the water constantly hitting off each other. Over time, they become worn down, smooth and rounded. This eventually forms sand. |
| What is a bay? | A curved area where waves have eroded the coastline |
| What is a headland? | An area of hard rock jutting out into the sea |
| Give an example of a bay and a headland | Dublin Bay and Bray Head |