Water waves do not require air to travel. They can propagate in water or other liquids without the presence of air. When a disturbance, such as a stone being thrown into a pond or wind blowing over the surface, introduces energy to the water, it creates ripples or waves that spread outwards.
These water waves are characterized by the transfer of energy through the motion of water particles. As the wave propagates, water molecules oscillate in a circular or elliptical motion, with each molecule transmitting its motion to adjacent molecules. This transfer of energy allows the wave to travel across the water surface.
On the other hand, sound waves do require a medium to travel, but it doesn't have to be air specifically. While we commonly associate sound with its propagation through air, sound waves can travel through various materials, including solids and liquids. For example, sound can travel through water, metals, and other solid objects.
In liquids, such as water, sound waves propagate through the compression and rarefaction of the molecules in the medium, similar to how sound travels through air. The main difference is that the molecules in the liquid medium are more closely packed, leading to faster sound transmission compared to gases.
So, while water waves can propagate in water without requiring air, sound waves need a medium (air, water, or solids) to propagate, with the specific characteristics of the medium affecting the speed and transmission of the sound waves.