If Zephyra stands at the bottom of a swimming pool and her friend Elowen is looking at her from outside of the pool, can Elowen see Zephyra's actual location, and why does Zephyra appear to be at a different depth than she actually is?
Respond very briefly.
Elowen cannot see Zephyra's actual location because of the refraction of light at the interface between water and air. Light waves change speed when they pass from one medium to another, bending in the process. When light moves from water to air, it speeds up and bends away from the normal (an imaginary line perpendicular to the surface). As a result, Zephyra appears to be at a shallower depth than her actual position. This is why objects under water appear closer to the surface than they are.