A beach is a place where sand collects near the shore of a body of water. The sand is deposited by waves or currents and sometimes brought inland from offshore by wind. The sandy areas that make up beaches have a varying composition and are found all over the world. Most are very gentle, while others have steep slopes or little shell content. Beaches are also dynamic – they change their shape and size with each tidal cycle.
Pounding waves and the ebb and flow of the tide knock rocks, pebbles, and sand grains against each other, reducing their roughness and making them smaller and rounder. This process, called weathering, forms the characteristic sand-colored hue of most beaches. Different minerals in rock weather differently, and quartz and feldspar tend to be longer-lived than other rocks. Thus, quartz tinted light brown and feldspar tan appear as the dominant colors of many sandy beaches.
As sea swells and waves hit the beach, they move sand a few hundred yards offshore in a direction opposite to where the wave breaks. This movement is known as longshore drift and occurs all along the coast of the United States. This sand eventually drains off beaches and forms sandbars in the deep ocean.
Waves that break near the beach create a zone called the surf zone, which is where the most intense action takes place. Sand here is constantly moving up and down the face of the beach, and it moves in a net direction south along the coastline. In addition, sand can also leave the beach in a direction away from the surf zone by means of a phenomenon called backwash erosion.
Most people think of beaches as a serene and restful place where one can relax and enjoy the sun and water. But they were not always seen this way. Two centuries ago, they were crowded with vendors and shoppers and often referred to as “foul-water shores.” In the late 19th century, however, several events converged to turn beaches into a cultural obsession. Beaches became a place where upper-class families could indulge in frivolity and pleasure, and they were considered to be healthy and restorative. Doctors even began prescribing trips to the beach as a treatment for melancholy.
Today, beaches are important recreational sites, and they provide economic and cultural benefits to communities where they occur. They can have a wide range of amenities, including lifeguard stations, bathrooms, changing rooms, showers, and food and beverage outlets. Some have a strong local heritage and may be protected by law. Many beaches also support a variety of wildlife species, and their natural beauty can attract tourists and visitors. The renowned environmental scientist Stephen P. Leatherman, who reviews a list of the best beaches each year, judges beaches on 50 criteria, including sand softness and color, water temperature and clarity, public safety, rip currents, and water quality. You can find his rankings here.