Waves are formed in three different ways, wind, earthquakes and gravity.
Gravity is responsible for high tides and low tides. High tide is when the water is the deepest and low tide is when the water is most shallow. The rise and fall of the water level causes waves to form
Wind can be light and cause small waves, these waves can be as small as ripples in the water. Young children can practise making waves by blowing on a bowl full of water.Wind could also cause very large waves that make being in water very dangerous. The type of waves that wind causes depend on how hard the wind blows.
Earthquakes under water pushes the water away from the epicenter of the quake and can cause some pretty large waves.Earthquakes often trigger tsunamis, also known as "tidal waves". When these waves travel in the deep ocean, they have a very high pace and a very long wavelength. They can travel right under a ship without anyone on board even noticing. But as they approach land, they are slowed down, so their size rises. The rise can be enormous, and that is what causes the damage near the coast. Earthquakes in the water causes volcanoes to form.
Waves wash some of the land and waves could cause tsunamis. Waves also cause ships to be destroyed and wash away sea animals from their natural habitat.