Why does the water turn white?

[Peripheral]

My wife asked me an interesting question this morning, "Why does water turn turn white on a waterfall"?
I told her it was the sun glinting on the water droplets. She folded her arms, like women do, and told me that it turned white in the shade as well. You know something, she's right. I am sure that some of you will know the answer please tell us so that I will be sure of getting some sleep tonight.

 

[Roger]

...and why is the head on a pint of beer white?

 

[RickAns]

Foam bubbles making it white?

 

[dick]

What about the white breakers on sea waves ?

 

[dick]

Foam bubbles making it white?

WHAT the beer ??

 

[captain clutterbuck]

Peri,

The sun is out, the sea is blue
but the waves are white when you view
But is it raining, raining in your heart ?

Why Waterfall Is White When Sea Is Blue? - You Ask We Answer

The sea is blue but waterfalls are white? All of this because of the lights and how our eyes perceive this lights.

youaskweanswer.net

 

[Moonraker]

The white colour is due to multiple scattering of light. The water falling produces lots of small bubbles that produce lots of reflections.
If you break a mirror or glass, this too looks white, again due to multiple scattering of 'white' light.