1A coin lies at the bottom of a beaker, just below the line of sight. Does the coin reappear as water is poured in and the level rises? Explain.
2Compare the sun seen when it is actually below the horizon with the coin seen in the steel glass after water is poured into it.
3Why does a pencil partly dipped in water appear bent at the surface?
4What are real depth and apparent depth? Which is greater, and why is this important for safety?
5Why do stars twinkle while planets do not?
6Explain why the sun can be seen about two minutes before actual sunrise.
7A diver under water looks up at a friend standing at the edge of the pool. Will the friend appear higher or lower than they really are? Give the reason.