What is the magnification factor of objects seen underwater compared to those seen in air?

When observing objects underwater, they appear magnified due to the difference in the refractive index between air and water. The refractive index of water causes light rays to bend when they transition from air into the water, impacting how we perceive distance and size.

The magnification factor commonly referenced for underwater viewing is approximately one-third, meaning objects appear about 33% larger than they do in air. This phenomenon is related to the way light travels through different mediums, leading to a visual distortion that can make objects seem closer and larger than they actually are.

Thus, when a diver looks at an object underwater, it appears larger or more magnified due to this refraction, supporting the idea that the appropriate magnification factor is indeed one-third or 33%. This understanding is crucial for divers to accurately assess distances and sizes of underwater objects.