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Homework Help: Goggles, depth perception, and swimming pools {Please aid a stumped student!}

  1. Apr 25, 2010 #1
    1. One person wearing goggles and one person without goggles are standing at the side of a pool. Both see a coin on the bottom of the pool, and both jump in to retrieve it. When they are underwater, the person without goggles sees the coin at a greater depth than it was when she was above the water. The person with goggles sees the coin at exactly the same depth as it was when she was on the poolside. Which of the two sees the coin at its actual depth? Explain the reasons for your answer.

    I have no idea. I mean I can pretty much figure out that it's the person without goggles that will see the coin at its actual depth and i think it has something to do with reflection, or refraction or something? Other than that though, I'm not a science person and I barely understand any of this, plus I'm a home school student. I look to you intelligent people for help.
  2. jcsd
  3. Apr 25, 2010 #2


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    Staff: Mentor

    Person without goggles doesn't see anything, as human eye is not able to accomodate under water.

    My guess is this question tries to address some problems with the refraction on the air/water phase, but seems to me like it is based on wrong assumptions and is in blatant disagreement with everyones personal experience. No idea what kind of answer the person that asked the question wanted.

    Most likely it is based on the fact that due to refraction on the air/water boundary submerged objects look closer then they are in reality. This can be easily explained if you try to draw path followed by light (and what our mind tries to make out of it assuming light path is always straight).
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