Water sounds different when hot

[MLyons]

So. Zak has just demonstrated to me that hot water coming from a kettle sounds very different (much deeper) to cold water coming out of a kettle... both going into the same container (in this case a mug). This came up after him going to make a brew and saying "the water is cold I can hear it" to which I replied "u wot m8 " He then got me to pour and I could easily tell the difference. Does anyone know of any other odd things like this and why does it happen?

[Bagnaj97]

Just Tom Scott's channel in general...

[Gerrard]

It was on an episode of QI ('N' series I think). I think they said they weren't quite sure why or how people could tell, but can't really remember.

[TooNice]

Right after reading this thread, I went to take a leak and instantly recognised that it was the sound of warm water being poured onto some cold water.

Fascinating

[Ttaskmaster]

It's an additive we put into the water at the reservoirs, so we can 'sound' for leaks and hear whether it's ice cold clean water or ground temperature sewage leaking out.... which obviously doesn't work, as we have so many leaks and no idea where they are!!


No I'm not serious. I have no idea what this is all about.
My hot tap makes noises once the warm water reaches it and expands the pipes along the way, that's about it. Beyond that, I can tell because I'll have just put the kettle on my own self and heard it boil.

[Bagnaj97]

It's an additive we put into the water at the reservoirs, so we can 'sound' for leaks and hear whether it's ice cold clean water or ground temperature sewage leaking out.... which obviously doesn't work, as we have so many leaks and no idea where they are!!

Don't be silly, there's no need for an additive, simply dowse for leaks. http://www.bbc.co.uk/news/uk-england...shire-42070719

[peterb]

Zak making a brew????? Never made one for me!

Back on track..

Hot water is less dense than cold. Might also be airated which would lower its density. The propogation of sound through the hot mug might make a difference.

But the sound a ketlte makes does change as the water heats and finally boils.

[Ttaskmaster]

Don't be silly, there's no need for an additive, simply dowse for leaks. http://www.bbc.co.uk/news/uk-england...shire-42070719

Doesn't work for actual leaks, though. Only underground water. I'm told there's a big difference...
Our lot say they specifically use divining rods to help them find the pipes, the results of which are then confirmed with modern methods.

The Guardian said there are, “calls for regulator to stop companies passing the cost of using discredited medieval practice on to customers”... which is fine. Instead of the cost of two bent tentpegs, we'll happily pass on the cost of sophisticated survey equipment and operations crews... !!

It's a shame, really. I quite like the idea of using magic to do my job. Makes me feel like a Level 8 Sorcerer... and besides which, I might as well roll a D20 to determine the outcome of our projects!!

[MLyons]

Zak making a brew????? Never made one for me!

Back on track..

Hot water is less dense than cold. Might also be airated which would lower its density. The propogation of sound through the hot mug might make a difference.

But the sound a ketlte makes does change as the water heats and finally boils.

He's a coffee connoisseur. Getting us some fancy coffee machine that works in mysterious ways. He makes coffee all the time here.

[Xlucine]

...Might also be airated which would lower its density...

Aeration is a whole other (hot) kettle of fish. Just 1% air will drop the speed of sound by an order of magnitude (from 1.5km/s to ~100m/s, which is even lower than the speed of sound in air).

Milk changes the noise a cup of tea makes as you tap the side with a spoon, and I believe it's mostly down to the emulsion doing a similar thing to aeration. Could also be temperature related, of course

[wazzickle]

Yeah, that would be the explanation I would tend towards - it makes a lot of sense that water would change properties a decent amount between just about to freeze and just about to boil; we have no real use for knowing the difference between the sounds they make, which is why they don't register, but we've all been exposed many times to the 4 different data points of 'hear cold water, know it's cold water', 'hear cold water, don't know', 'hear hot water, know it's hot' and 'hear hot water, don't know' that we would be subconsciously trained into having a skill we didn't realize we had, that we could activate simply by asking the question 'is this running water hot or cold'.

Makes you wonder what other sets of skills we have that we're not aware of.

[Zak33]

Makes you wonder what other sets of skills we have that we're not aware of.

you're right, it does.

I didn't know people didn't know about the boiling water sound thing... I just assumed everyone knew it. Therefore, you lot all know something I don't.

(like ... Zak your zip's undone)

[Pob255]

I think I know what's happened here . . .

Zak is a witch! Burn him!

[Lucio]

Strongly suspect that any sound differences are due to density and flowrate altering based on temperature

[Hoonigan]

It's also true that boiling water freezes faster than cold water. As weird as that might sound.

[Splash]

It's also true that boiling water freezes faster than cold water. As weird as that might sound.

water that has been boiled an allowed to cool, not boiling.