If you are picking up a coin on the bottom of the pool can you just reach for where the coin appears to be why or why not?

No, you cannot just reach for where the coin appears to be because of the refraction of light in water. When light passes from air into water, it bends, making objects appear higher and closer to the surface than they actually are. This optical illusion means that if you reach directly for the coin as it appears, your hand will likely miss it. You need to adjust your aim to account for this distortion.