A beach is a natural feature that forms along the shoreline of bodies of water like oceans, rivers, lakes, and some large ponds. Its most distinctive characteristic is the accumulation of loose particles like sand and pebbles. Beaches form through a complex combination of factors over a long period of time, including weathering and erosion. Weathering is the process of rocks breaking down into smaller pieces by wind, rain, and other natural forces. Erosion is the process of waves pounding against the coastline, gradually wearing away at the rock. Over time, this eroded material gets washed up by the tides and carried away by currents to form beaches.
Beaches may also contain a variety of other materials, from larger rocks to marine organisms such as shells and seaweed. Sand, pebbles, and other small particles are the most common beach materials, but sometimes sandy beaches can have layers of silt or clay too. Silt and clay are generally the result of weathering, where sand grains have been worn down to finer sizes by the constant action of waves on a rocky coastline. Mud is usually not found on a beach, but instead is suspended in the water or in the marshes and sounds behind barrier islands.
A sandbar is a strip of sand that extends out into the water, usually a short distance from the coastline. As a bar forms, sand is continually deposited on it by the turbulence created by surf and backwash of other waves. This sand is also added by rip currents and the erosion of other beach materials, such as seaweed. In addition, sand is periodically shifted from the beach to the bar by a phenomenon called longshore drift.
Many beaches are polluted, especially in urban areas. Waves wash up garbage from cities and suburban neighborhoods, while sewage seepage from inland pipes often finds its way to the shoreline. These pollutants can harm the health and safety of beachgoers, particularly children.
People use beaches for a wide range of activities. Some people enjoy the solitude of a quiet beach without any distractions, while others find recreation and relaxation through surfing, volleyball, or simply walking on the sand. Beaches are popular destinations for families and tourists, as well as a retreat for local residents seeking to escape the hectic pace of city life. Throughout the twentieth century, beaches have become synonymous with the notion of a simple lifestyle that enables introspection and self-awareness. Beaches remain popular with middle-class Americans, and their popularity is increasing as inexpensive mass transit systems allow city working people to take a day trip to the coast. This article was originally published in November 2004. It was updated in January 2019 with additional information. This version features a new header image and links to related articles. It was also reviewed and revised for accuracy.