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Assumption: The only lights I have are candle, table lamp, and sunlight.

What would I need to create visible reflection of an object in the shallow water contained in a 5 liter bucket? Is it even possible anyhow?

What kind of light out of the three will maximize the visibility of the reflection in this case?

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I can't get a grip on that phrase "distinguishable reflection". What do you mean by that? Is this some kinda home experiment you wanna do? ;-) –  Waffle's Crazy Peanut Apr 17 '13 at 11:10
is the 5 litre bucket full? Is this a homework question? Have you tried coming up with any solutions yourself so far? if so, what have you tried? –  RhysW Apr 17 '13 at 11:11
@RhysW: This doesn't look like a homework question to me. It looks like some home-experiment..! –  Waffle's Crazy Peanut Apr 17 '13 at 11:12
@CrazyBuddy ive had homework questions before that were 'how would you do this? try it and tell us what you found' i just want to clarify :) –  RhysW Apr 17 '13 at 11:14
@RhysW ? Is this a homework question? Have you tried coming up with any solutions yourself so far? I am NOT in school, nor I am a Physics student, nor I intend to become one. My hobby is "Photography". I live in an industrial area which doesn't have any ponds/lakes so I was wondering if there is some way to get creative at home with a bucket of water. Well, the bucket is basically of 10 litres. I can fill it to the brim if it is required. –  abcd Apr 17 '13 at 11:38

1 Answer 1

up vote 3 down vote accepted

If the problem with shallow water is that you see the walls and the bottom instead of only the reflection, I would just use a black bucket. Or somehow make bucket's inners black.

Moreover a bucket is a bit unpractical in this case, just a really black tray with water should suffice.

Another option is to make water black itself, like using coffee.

UPD All three light sources should behave identically in terms of reflection provided the water/tray is really black. However in real world the brighter the light the darker color is required. I just advise you to try it yourself.

There is another matter you might be interested in. The portion of light reflected greatly depends on the incident angle. If the light goes almost parallel to the surface it will be reflected almost completely. So if you are trying to imitate a reflection of houses or trees on a river bank (tangent light) you'll get brighter reflection than if you are looking straight down into the bucket.

The logic is quite simple. When the light hits the water most of it passes through the surface, the smaller part is reflected. In deep water the light that passed through eventually dissipates and does not return back. All you see in that case is the reflected light.

In shallow water the light hits the bottom and bounces back riving with one that reflected.

So all you need to make reflections visible is to eliminate the light that comes back from the bottom. Either paint the bottom black or make water black.

However I don't think it is how I was reasoning. I've just remembered an analogous situation with windows. When you are indoors at night with room light on your windows are essentially mirrors.

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Great!! I will definitely try with the black surface. Now I really wish I were a Physics student! What is the logic behind your answer, BTW. Just curious to know. –  abcd Apr 17 '13 at 11:48
Is reflections in a cup of black coffee visible enough? Sorry, I haven't seen or drunk black coffee so I don't know. –  abcd Apr 17 '13 at 11:50
@AnishaKaul Just make coffee without milk, I thought it should be black. I mentioned coffee because it seems to be readily available. You can use ink instead or something like that. –  Yrogirg Apr 17 '13 at 12:01
Great explanation! Thankful to you. –  abcd Apr 17 '13 at 12:02
QUE: What kind of light out of the three will maximize the visibility of the reflection in this case? –  abcd Apr 17 '13 at 12:19

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