A beach is land that is next to a body of water such as a lake or ocean. Usually it is made up of sand, gravel or shingle. It may be large or small and is often changed by the action of waves on it.
The sand on a beach can be white, black, tan or yellow and is formed from the eroded exoskeletons of tiny creatures called corals. It is a very important part of the ocean ecosystem.
Sand grains are made of quartz, feldspar, or other minerals. They are light or translucent and can be oxidized, leaving them with a brown to gray color. The sand grains are sometimes iron-stained, which leaves them with a yellow or brownish color.
In some areas, such as Hawaii, the sand is made from black basalt. On beaches in other parts of the world, such as Harbour Island in the Bahamas, sand is made from corals that have broken down into small sand-sized pieces.
During fair weather, sand is carried by the wind on to the beach from water depths as great as 30 feet. This sand is pushed outward in a seaward direction during storms, but it remains on the shore for most of the time.
Other sources of sand on beaches include sand bars, tidal deltas and bluffs that rise up to the beach head. Waves also carry sand and shells from the continental shelf, which is the largest source of beach sand.
Some sand on the beach is actually the bottom of shallow pools. This sand is sometimes called scouring or plow sand. This sand is not very compacted and is easily washed away.
There are different types of sand and some types are better for certain animals to live in. For example, sand that is very soft can be a good place for crabs to live because they can get food out of the water.
A sand beach can be very steep and have a cusp or it can be sloping and not very steep. When a beach is very steep, the waves will come in and out very quickly and the beach will be worn down by the waves.
In some countries, the wind will blow sand off of the beach and make it into small hummocks. These hummocks will join up to form foredunes and dunes. If the beach is well supplied with sand, several rows of dunes will be created.
These dunes can bury fertile soils and other things that are close to the beach and move them inland. They may also bury buildings or woods that were on the beach.
The beach is very important for many different people because it is a place where they can go to relax and enjoy the sun. It is also important for some other animals, such as birds, that use it to nest and lay their eggs.
The beach is a very important part of the ecosystem and it is changing constantly, which is why we need to take care of it. It is very important to have a clean beach that is safe for people and animals to walk on.