Explaining the Sun's Effects on Rough Surfaces Covered in Water

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Discussion Overview

The discussion revolves around the physical phenomenon of why rough surfaces covered in water appear darker in sunlight. Participants explore various explanations related to light behavior, including reflection, polarization, and the interaction of light with different mediums.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that the darker appearance may be due to the polarization of light reflecting off the water.
  • Another participant proposes the idea of total internal reflection as a possible explanation, though they acknowledge that this would prevent any light from being seen at all.
  • A different participant discusses the reflection of light off the water's surface and its subsequent absorption by the denser medium, indicating that not all light penetrates the water.
  • Some participants note that the angle of incidence and refraction might play a role in the observed effect.
  • It is mentioned that the coating of water leads to more light being reflected rather than scattered, which could contribute to the darker appearance of the surface.

Areas of Agreement / Disagreement

Participants express various hypotheses regarding the phenomenon, and there is no consensus on a single explanation. Multiple competing views remain, with different aspects of light behavior being considered.

Contextual Notes

Some assumptions about light behavior, such as the effects of angle and medium density, are not fully explored or resolved. The discussion does not clarify the specific conditions under which these effects occur.

Who May Find This Useful

This discussion may be of interest to those studying optics, physics, or anyone curious about the interaction of light with surfaces and materials.

azatkgz
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Rough (not smooth) surfaces often appear to be darker in sunlight when they are covered by water.How can we explain this physical phenomen?
 
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I'm no expert in this by any means, but I suspect that it's due to polarization of the light coming back from the water.
 
Can it be total internal reflection.In this case light cannot go out from the liquid.
 
Not total, or you would see nothing at all. Honestly, though, wait for someone with appropriate knowledge to help you. I'm not qualified. I just guessed at the polarization because a very long time ago when I wore Polaroid sunglasses, a puddle on a sidewalk looked to be a couple of miles deep. Without the glasses, it was just a puddle.
 
First off you will have some of the light reflected off the surface so not all the light makes if through the water to the object.
Then some of the light is also reflected back into the water when it encounters the boundary again on its way out.
You will also have some of the light absorbed by the denser medium.

At least the would be my guess.

This would be true for both smooth and rough objects though.
Maybe it has to do with the angle of incidence and the angle of refraction.
 
Last edited:
The effect has more to do with the fact that by coating the object with water, a good deal of light is reflected off the surface, instead of being scattered in random directions by the rough, dry surface.
 

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