waves

[blue orchid1]

Oceans have huge waves, is it because the water is being pulled from the earth and then when it comes crashing down it is because of gravity?

Why does it not happen in lakes is it because it is not as deep?

[Teddio]

Waves are due mainly to the effect of wind blowing over the surface of the water. A large body of water, such as an ocean, has a huge surface area for the wind to act on and, consequently, large waves can result. The depth of water is an issue only when deep water waves move towards the shore. Tsunami waves have a very small amplitude when travelling over deep water but "bunch up" and get bigger when they reach shallow water.
Wave action can also result from tidal movement and tectonic movement on the sea floor (tsunami)

[Bazile]

Apologies in advance if this is a silly comment - but I thought the moon had something to do with it - yes , no ? -
or is it tides ?

[gen2]

Bazile, The moon only directly influences the tides.
Teddio has already stated that tidal movement can then cause waves. That is particularly the case where tides flow into or over shallow areas (estuaries, sandbanks), over an underwater obstruction (submerged mountain), through a narrow opening or around an obstruction such as an island.