Waves
Waves are what can erode rocks from the coast into caves and cliffs. Features like beaches form from the waves carrying sediment which forms into a beach. That's because waves carry sediment which places on shore to create beaches. The energy in waves is a very high amount, because waves get energy from high strong winds. Waves in lakes or small ponds are only made from miniature breezes, like calming regular wind in summertime or springtime. Although, the waves do change once they hit the surface. Waves start to drag to the bottom as they are reaching shallow water.
The major force of erosion along the coasts are waves. Erosion is what makes the waves shape the coast by breaking down rock and transporting sand and other sediment to different places. If you've ever seen large waves slapping themselves against larger rocks, then you have experienced one major way of how waves erode. This is because over time, those rocks will eventually have bigger cracks in them then they had to start with if any at all. As a wave starts approaching shallow water, the waves then pick up sediment, such as sand and gravel. Then, once the wave hits land, the sediment wears away on the land.
Waves will also sometimes change direction. That's because the energy is concentrated on headlands. A part of the shore that sticks out into the ocean is a headland. The reason why headland sticks out of the ocean is because headland is rather a tougher type of sediment that is able to resist from erosion from waves. After time though, waves will even out the shore line from eroding it.
Wave Erosion Landforms
When you see waves hitting a rather rocky coast continuously, that's because the waves will keep aiming into that direction to erode the headland fully. Along a steep coast is where waves erode the base of land. The easier it is for waves to erode sediment when the rock is softer, so the sediment will break down with less wave splashes.
Deposits By Waves
Waves shape a coast when they deposit sediment, forming coastal features such as beaches, spits, and barrier beaches. Once the waves are slowed down, that is when deposition occurs. Waves will drop their sediment once they become slower in motion. Once a river delta drops its load of sediment, it's depositing, very much in the same way as waves. Waves then form a beach when they drop their sediment along the shore. A beach is an area where there is wave-washed sediment along the coast. Most beaches that you would usually see would be made of sand, although there are some beaches that are made of sea shells or even coral that is stacked up from the waves.
If you've seen waves coming up-shore to a beach, you would probably notice that waves hit shore at an angle instead of hitting the surface in a straight process. There is a current that waves make by being in an angle. Sometimes when waves bring sediment to shore, some of the sediment rolls down into that current in which is called a long-shore drift. A result of a long-shore drift is something called a spit. A spit is a beach that projects like the shape of a finger into the water. Spits usually occur when an obstacle is in the way of a long-shore drift, or where some of the coast turns.
Ocean Spit Image
An ocean spit.
Sandbars and Barrier Beaches
When waves carry sand or sediment, they can sometimes stack on top of each other. When they are stacked on top of each other, it's called a sandbar. A sandbar is not very much different from barrier beaches.
A barrier beach is what forms off of storm waves piling up sand, above sea level forming a narrow island parallel to the coast. Many of these barrier beaches are what some people find nice to build there houses on. The storm waves that also build up the beaches can surely wash them away as well though. The damage that earthquakes or hurricanes can bring to these houses can put them in jeopardy, so people must be prepared to live in a place like this.