How do islands float? What is underneath them?

How do islands float? What is underneath them?

Islands don't float, they are connected to the seabed. Think of islands as mountains that happen to be out at sea and are mostly covered by water.

Islands form by many processes. Most open ocean islands (Hawaii, Azores, Canary Islands) are formed by volcanoes. Islands, such as the UK and Ireland, are actually part of a continental plate and happen to be surrounded by a low-laying surface which has been flooded by the sea.

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