If you open your eyes underwater, can you see out of the water?

Another example of total internal reflection can be seen when you are underwater. If you look straight up out of the water, you will see the sky and any other visible surroundings directly above the water. If, however, you look out of the water at an angle of 48° or more from the vertical, you will not see out of the water, but instead will see a reflection from the bottom of the water. The next time you are in a pool or a lake, try looking up out of the water and you will see a point on the surface where you no longer can see out of the pool, for the light has reached its critical angle.


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