# How much liquid water to become opaque? **URL:** \ **Category:** Factual Questions\ **Created:** [February 24, 2012, 10:33pm UTC](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885 "2012-02-24T22:33:25Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Fuzzy\_Dunlop](https://avatars.discourse-cdn.com/v4/letter/f/848f3c/32.png) [@Fuzzy\_Dunlop](https://boards.straightdope.com/u/Fuzzy_Dunlop)\ **Post date:** [February 25, 2012, 11:35pm UTC](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885/21 "2012-02-25T23:35:48Z")
> [@ZenBeam](#): > > Didn’t want to get into it by pointing out that your post had fuck-all to do with whether the picture on the page was a valid example or not. None of you could explain why the pool is blue right to the edge. > > But feel free to continue your Jr. High comments. Sorry, I could have been clearer but I thought my post was amusing. My point was every other picture of a pool also looks that way - blue right to the edge. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [February 25, 2012, 11:42pm UTC](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885/22 "2012-02-25T23:42:25Z")
> [@ZenBeam](#): > > Didn’t want to get into it by pointing out that your post had fuck-all to do with whether the picture on the page was a valid example or not. None of you could explain why the pool is blue right to the edge. > > But feel free to continue your Jr. High comments. I can’t explain the physics of it, but it is clear that it looks that way in every single container of water no matter how pure. I was not kidding about being in a lab with ultra pure water. We use it for semiconductor grade materials (even if 99% of our materials aren’t). Water is blue and all reputable sources will tell you so. It’s a little strange that you would continue to suggest that the blue color was fake when every single peice of evidence suggests that it isn’t. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [February 26, 2012, 12:17am UTC](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885/23 "2012-02-26T00:17:40Z")
> [@WarmNPrickly](#): > > It’s a little strange that you would continue to suggest that the blue color was fake when every single peice of evidence suggests that it isn’t. In the interest of equal time: Yep, every single time I look at my clear glass full of water, I notice the blue tinge. It’s like smurfberry juice up in that glass. There _is_ a reason this discussion is endless, as I alluded to above: There is a threshold process involved, some specific volume below which pure water _never_ looks blue, a volume above which pure water _always_ looks blue, and a range of volumes where it depends on ambient light and the container. Unlike, say, gold, which will always look golden in its solid form due to quantum effects, water is a little more complex than that. Not much, but enough so that honest people can get into an endless ‘debate’ on the topic. There, is that up to at least Senior High level? 😉 ---
**Author:** ![Astral\_Rejection](https://avatars.discourse-cdn.com/v4/letter/a/258eb7/32.png) [@Astral\_Rejection](https://boards.straightdope.com/u/Astral_Rejection)\ **Post date:** [February 27, 2012, 3:31pm UTC](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885/24 "2012-02-27T15:31:17Z")
> [@ZenBeam](#): > > Didn’t want to get into it by pointing out that your post had fuck-all to do with whether the picture on the page was a valid example or not. None of you could explain why the pool is blue right to the edge. > > But feel free to continue your Jr. High comments. I can help. Grab a cup of coffee. It should be uniformly dark up to about a half inch of the side, where you can start to see a gradient in the darkness of the coffee. In the pool photo, there likely is a slight difference in the color of the water, but it’s too fine of a difference to show up in that photo. So, why is this? What you have to remember is, you’re not just seeing light reflecting from that specific spot. You’re also seeing light bouncing from the bottom of the pool, the opposite side, and who knows where else, all of which have passed through a large amount of water. This lends water its characteristic blue color uniformly throughout the pool. Does that help? Let me know if you need further clarification. [Previous page](https://boards.straightdope.com/t/how-much-liquid-water-to-become-opaque/613885.md?page=1)