Final answer:
Internal waves are significantly larger than surface waves, occurring at interfaces between layers of different densities such as temperature or salinity gradients in the ocean, whereas surface waves are found at the water-air interface and have smaller amplitudes.
Step-by-step explanation:
One of the most obvious physical differences between internal waves and surface waves, besides their location, is (b) Internal waves are larger than surface waves.
Internal waves occur at the interface between layers of different densities, such as in the ocean where there is a mix of warm and cold water or water with varying salinity. These waves can have very large amplitudes, much larger than the surface waves we see on the top of the ocean. Internal waves are significant in ocean dynamics as they can mix nutrients and affect underwater navigation.
In contrast, surface waves are typically smaller in amplitude and are found at the interface between the water and the air. While internal waves might not be visible to the eye as they occur beneath the surface, their presence can sometimes be inferred by patterns on the surface or by scientific instruments.