# Why does hot water sound different from cold water?

**URL:** <https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934>\
**Category:** Factual Questions\
**Created:** [August 8, 2002, 8:19am UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934 "2002-08-08T08:19:30Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![simonlb](https://avatars.discourse-cdn.com/v4/letter/s/ecc23a/32.png) [@simonlb](https://boards.straightdope.com/u/simonlb)\
**Post date:** [August 8, 2002, 8:19am UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934/1 "2002-08-08T08:19:30Z")

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Anyone ever tried this?

Get 2 jugs the same size and fill one with cold tap water, and the other one with an equal amount of boiling water from a kettle.

Next pour each jug in turn into a sink and listen. The hot water sounds different from the cold water. Why?😕

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**Author:** ![jb\_farley](https://avatars.discourse-cdn.com/v4/letter/j/9d8465/32.png) [@jb\_farley](https://boards.straightdope.com/u/jb_farley)\
**Post date:** [August 8, 2002, 9:20am UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934/2 "2002-08-08T09:20:35Z")

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perhaps the higher levels of humidity around the boiling water muffles sound.

jb

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**Author:** ![tcburnett](https://avatars.discourse-cdn.com/v4/letter/t/c5a1d2/32.png) [@tcburnett](https://boards.straightdope.com/u/tcburnett)\
**Post date:** [August 8, 2002, 10:34am UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934/3 "2002-08-08T10:34:38Z")

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The molecules are moving quite rapidly in the hot water so the hot water is actually a little ‘slicker’ than cold water and reacts to friction, air, surface tension and contact with the sink differently.

Hot water, knowing it is hot, simply has an attitude.

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**Author:** ![fierra](https://avatars.discourse-cdn.com/v4/letter/f/58956e/32.png) [@fierra](https://boards.straightdope.com/u/fierra)\
**Post date:** [August 8, 2002, 12:09pm UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934/4 "2002-08-08T12:09:13Z")

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The boiled water will also have less dissolved gas in it, although I’m not sure exactly how much difference that would make to the sound. Dissolved air comes out of solution in water at standard room pressure at about 50 degrees Centigrade. You could try heating some water to about there (watch for the teeny tiny little bubbles on the base & sides of the boiling container), and some to just under that point (not much difference in temperature related viscosity) & see what they both sound like to see if this is the main cause.

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**Author:** ![Popup](https://avatars.discourse-cdn.com/v4/letter/p/94ad74/32.png) [@Popup](https://boards.straightdope.com/u/Popup)\
**Post date:** [August 8, 2002, 12:24pm UTC](https://boards.straightdope.com/t/why-does-hot-water-sound-different-from-cold-water/122934/5 "2002-08-08T12:24:43Z")

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> [@](#):
>
> \*Originally posted by fierra \*  
> \*\*You could try heating some water to about there … and see what they both sound like to see if this is the main cause. \*\*

Great thinking. However, if you take water that has been boiled relatively recently, and then cooled down so that no gasses are dissolved (the way you make clear ice cubes!), it still sounds like cold water.

According to [This table at pump.net](http://pump.net/liquiddata/viscosityofwater.htm) the viscosity of water changes quite a lot with temperature:  
at 100°C the viscosity is only a sixth of that at freezing. I believe that it’s the viscosity that’s the main culprit.