Hot water

[fairkatrina]

How come hot water goes cloudy? (Yes, it's *that* time in the evening...) From what I remember of school science, the molecules that form the water would start to seperate as it heats, surely making the water more transparent rather than opaque? Or is it the molecules vibrating that produce a 'cloudy' effect to our useless eyes?

[nightmare]

I was not aware that water went cloudy when hot.
How is it being heated ?
The apparent cloudiness could be caused by tiny bubbles of dissolved gases coming out of solution as the water is heated.
I need more info. on what you mean before I can give a definite answer.

[himupnorth]

Good answer nightmare, the "clouds" are indeed bubbles of gas. Curiously as the temperature increases the amount of gas which can be dissolved in a given amount of water decreases (think - cold pop is fizzier) you've just observed the dissolved gases undissolving (mainly oxygen and a tiny amount of carbon dioxide). Have you also noticed how the kettle gets noisier when heating but goes quiet just before boiling? Same reason noise from gas escaping, all gas gone - quietness reigns!

[fairkatrina]

Thanks both, you've satisfied my 2am puzzling. Nightmare next time you're wandering inanely around the house in the middle of the night go into the bathroom and turn on the hot tap, you'll notice that the water coming out is milkier than that from the cold tap, hence the question.

[fairkatrina]

Oops forgot to end the bold lol

[nightmare]

fairkatrina
just how hot is the water in your house ?
The water from my hot taps is in no way milky.
I am not in the habit of wandering inanely or in any other manner in the middle of the night

[Space]

I guess it depends on what water heating system you have.
If it's an immersion heater, the hot water is stored for a while time so the bubbles have time to escape,
whereas in a gas heater you get the water that has just been heated so it still has the bubbles.
Just a guess.