Beaches are mainly created from tides and ocean currents that come up over the land. The repetitive motion of the tides coming in and going out causes weathering and erosion of the land, and it deposits sand, shells and seaweed on the shore.
A beach is a narrow, sloping strip of land that lies along the edges of an ocean, lake and certain other bodies of water. Through the years, the tides have weathered large rocks into small grains of sand. Beach materials carried by wind or the tide can travel long distances. For example, as the tide comes in, it deposits ocean sediment on the beach, then takes a little of the land with it. The churning of the water changes the sediment over time and deposits it somewhere else. Beaches are always changing because the tides and weather can bring new material, or take material away.
Seasons also have an effect on beaches. During the winter, storms lift sand in the air and carry it away. This can cause the beach to erode and create a sandbar, which is a narrow, exposed area of sediment and sand. During the summer months, waves come in and retrieve sand from the sandbars and build the beach back up again. This is why beaches are often wider with a gentle slope in the summer and narrower and steeper in the winter.