Bays
A bay is a large body of water connected to an ocean or sea formed by an inlet of land due to the surrounding land blocking some waves and often reducing winds. There are various ways that bays can be created. The largest bays have developed as a result of continental drift. Another way bays are formed is by glacier and river erosion. Most bays are formed by the folding of the earth's crust as well as coastal erosion due to waves and currents. Currents can make waves more constant, while soft rocks will allow erosion to have a stronger effect. Any hard rock is eroded less quickly, leaving headlands.
This a picture of a bay that has been formed by the combination of wind, glacier, and mostly water erosion. Even though there is not a picture showing a bay today, there is evidence that bays still exist today.
Beaches
A beach is the area in which sediment is deposited along the shore. Beaches are composed of loose sediments deposited and moved about by waves along the shoreline. The size of sediment particles depends on the energy of the waves striking the coast and on the source of the sediment. Beaches pounded by large waves or formed on rocky coasts usually consist of coarse materials such as pebbles and cobbles.
Beaches are found along most coastlines of the world. They are constantly changing due to the water, waves, and wind. These factors move the sand,and can change the shore of a beach.