A kitchen has twin side-by-side sinks. One sink is filled with water, the other is empty.
(a) Does the sink with water appear to be deeper, shallower, or the same depth as the empty sink?
(b) Choose the best explanation from among the following:
I. The sink with water appears deeper because you have to look through the water to see the bottom.
II. Water bends the light, making an object under the water appear to be closer to the surface. Thus the water-filled sink appears shallower.
III. The sinks are identical, and therefore have the same depth.
This doesn't change by putting water in one of them.