A beach is a landform formed by the accumulation of loose particles like sand and shells along the edge of a body of water. The word is most often associated with the ocean, but beaches can also form along rivers and some lakes.
The formation of a beach requires a lot of energy, which is provided by waves and currents. As waves pound against the shore they carry some of the loose sediment they contain. This material is then deposited where the wave breaks, usually on the sand at the shoreline. Over time this process builds up the size and shape of the beach.
Some beaches are made of sand that was originally from the land, while others are composed of sand originating from other sources. The sand from the land is called terrigenous, and it is typically siliceous (see the photo below). Beaches in areas with volcanoes tend to be made of volcanic sand that’s rich in minerals such as iron. Beaches near coral reefs may be composed of calcareous, or coralline, sand that contains the shells and skeletal fragments of sea organisms.
In addition to the type of sand, there are other characteristics that define a beach. For example, a beach must be relatively free of rocks larger than pebbles (see the photo below). It must also have a uniform slope that gradually descends into the water. And it must be fairly wide and accessible to people.
Beaches are very dynamic landforms that change in size, shape, and composition on a constant basis, often over the course of only weeks or days during major storms. They also serve as a buffer that protects the land that is behind them from erosion by dissipating the energy of waves.
Besides being a fun place to play and relax, beaches are also home to many animals, including birds, crabs, fish, insects, and even sea turtles. They also support a diverse plant community, with sand dunes providing a habitat for a number of plant species.
One of the most interesting types of beach is a sandbar. A sandbar is a thin, often flat strip of sediment that lies between the sea and a rocky coastline. Sandbars are created by turbulence generated by swirling currents, which carries the sand downstream. As the sand moves, it forms a bar that’s usually several feet deep and stretches for a few miles. They can be found in all oceans, but are especially common around Florida. A sandbar can be very lively, with groups of people gathering to picnic or play games on the sand. In addition, sandbars are popular with boaters. These visitors bring food and drinks to share, which can add to the fun atmosphere. This is why sandbars are sometimes known as “party bars.”