Visibility when looking down through a Glass Bottom Boat

[gutman]

TL;DR Summary

Why is there better visibilty when viewing under water through a glass bottom of a boat rather than say looking over the side of the boat?

Why is there better visibilty when viewing under water through a glass bottom of a boat rather than say looking over the side of the boat?

 

[berkeman]

Welcome to PF.

What are your thoughts on this question? Have you been able to find anything with your Google searching so far? How familiar are you with the index of refraction of clear materials?

 

[gutman]

The only reference I could find is on Wikipedia "glass-bottom boat", where it says "The view through the glass bottom is better than simply looking into the water from above, because one does not have to look through optically erratic surface disturbances.". That was my intuition as well, but I'd like to go beyond imtuition... I hope to get some support (or not) for this claim, and more details.

 

[Ibix]

The non-flat surface of the sea means that light paths bend randomly at the surface, distorting images seen through it. You can see this effect in a swimming pool, or even a bowl of water.

Additionally, the sky above you is brighter than the sea below, so you see a lot of light from above washing out what's inside. It's much like looking into a window from outside on a sunny day - you see the exterior world reflected and not much of inside. When you're in a viewing boat the interior will be dim so you don't see so much reflection.