Why does the waves move up and down and not in front?

Answer 1

All waves are the result of some energy input such as a sudden atmospheric pressure drop producing air movement (wind) that could affect the surface of an ocean. The wind hits the water surface lowering its height (= a sudden change in potential energy), the depth of the height reduction depends on the amount of influenced energy and this surface lowering will produce an opposite reaction further away from the starting point making the surface raise the same amount as it sunk from the beginning. The distance between the minimum point in the valley and the maximum point oh the "hill" is called the wave length. Now if you could watch the waves from the side it would appear as if the water actually was moving in one direction. However, the water molecules stays at its original position i.e. the water itself is not travelling, it is merely acting as the media for the (energy) wave to travel within.