color of water?

The Mermaid Queen

TFP Expert
LifeTime Supporter
Mar 28, 2007
2,522
Northern KY
Guess this might actually qualify as a physics question, but here goes!

On PF last year, I read a blurb that water, pool water specifically, looks blue because of the reflection of the blue sky. That sounded good to me, at the time...

I have a white tub, with white tile around it, just barely off-white walls and ceiling, incandescent lighting, taupe towels, light tan-ish vinyl flooring. Not a bit of blue anywhere. So why does the water in my tub look blue??
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
It's because of the earth's rotation induces a centrifugal force onto water molecules, which, when combined with the natural magnetic field, cause the water particles to... Nahhhh... I'm just making that up. I got nothin.

I'm pretty sure that this falls into the category of questions like "Why is the sky blue?", which has been asked since the dawn of the word "blue". I think that water tends to absorb the red spectrum of light, which helps, but I believe that there are some complexities between the light transmission and the light reflectivity (of both water AND air) which come into play, which I wouldn't understand.
 

Butterfly

TFP Expert
LifeTime Supporter
May 30, 2007
10,045
South Carolina
Now Grace, you know that blue water usually means no algae! 8) AND, blue water is beautiful!

Couldn't resist. :roll: btw, thanks again for my avatar :)

Joyce
 
G

Guest

i always herd the darker the surface the greener and the lighter the bluer,

but we have one bath tub thats white, with dark i think slate tiles around it and the water always looks clear, and another one with light blue tiles and the water still looks clear, the waters clear, you are just seeing the reflection of the surface it in.
 

ktdave

LifeTime Supporter
May 8, 2007
888
Katy, TX
My surface is almost as dark as it gets (midnight blue pebbletec), and its a dark blue. No hint of green.

And clear as can be, thanks to TFP!

For example
 

Belldiver

Well-known member
Sep 7, 2007
344
Lafayette, Louisiana
ktdave said:
My surface is almost as dark as it gets (midnight blue pebbletec), and its a dark blue. No hint of green.

And clear as can be, thanks to TFP!
I really like what you did with your colors...light in the shallows and dark in the deeper water to make it look that much deeper. Are you worried about the dark finish absorbing too much heat from the sun and making the water too warm in July/August? That's my only concern. I live in Louisiana (not far from you) and some friends of mine have pools (small) that almost get TOO warm in late summer.
 

ktdave

LifeTime Supporter
May 8, 2007
888
Katy, TX
I got started up (finished construction) the first day of August this year. I have no other point of reference, but through the hot days of August (95-100) the hottest the pool got was 90. That was only a couple of the hottest days. I would say of the 45 days we've been open, the average is about 86-88, which is where we like it.

One thing that might help us is, as you can (barely) see in the picture, the pool is very close to the house (right side of pic), which is on the west side of the pool. The pool gets shaded from the house beginning about 3:30-4:00 and is totally out of the sun at 5:00.