You can hear the difference between hot and cold water


Originally published at:


I can tell the difference hearing the cold water turn warm after I turn on the shower


It’s a really simple and straightforward video, the concept behind it is also approachable and quick to grasp. Love stuff like this being a good way to transition discussion to other scientific concepts.


The hot water sounded like cocoa. I guess I always thought the muffling effect came from the fact that the hot liquid is usually something other than water, or water being added to something else.



This is also true for petroleum and solvent contamination in water even at low levels, but it’s hard to quantitatite that (it comes across like dowsing to someone who doesn’t spend time with contaminated water) but I’ve been pretty sure when clean looking water is not clean, well before I got the lab data back. It just sloshes wrong.


The image that came to my mind was hot tea being poured.


For a while I’ve noticed that I could tell when the hot water ran out while I was filling the bath, but I couldn’t work out quite how. I was wondering if it was just the timing, with my brain alerting me after five minutes or whatever had passed; the competing hypothesis was that I was hearing a change in tone as the hot changed to cold, but when I deliberately listened I couldn’t tell what the change was. I shall have another go later after watching this video.


Oh, that guy again. They should let some other people have a turn on Youtube.


Sometimes you can hear a change in the sound of the clicking of the spoon against a ceramic cup as you stir your coffee. I assume that’s due to cooling off too.


Less than 6 hours. Beats out the usual heres the video you saw 2 days ago.



I always thought the same, especially as it approaches a roiling boil. Cold water always sounded - I don’t know - “slappy”?


Came here to say the same thing. I turn on the water, it runs cold for a bit, and I can tell that it’s getting hot from the sound it makes.


You can hear the difference between hot and cold water when someone jumps into the shower. The resulting screams are quite distinct from each other.


Of course you can.

It’s an “Ah, ah, ah” sound under hot water, and more of a high-pitched yip if you’re standing under cold.

ETA: dammit, @hecep.



i once got into a bargument about this. i wish i had known the proper science behind it, but at the time i just knew they sounded different. so nice to have vindication!


They …did?

Unless you’re referring to the person who made the main part of this video rather than the channel owner.
I’ve had much experience of the latter, this is the first time i’ve even heard of the former…

I think i may be seeking out more of the former guy now though :slight_smile:


You can feel the difference, too. Taking a kayak out through surf in 40 degree (farenheit) water feels like getting punched in the gut.


Are you sloshing sealed containers; or do the viscosity effects actually kick in below the odor detection threshold for some of these contaminants and/or with contaminants that are effectively nonvolatile?


yes but not neccesarily, and yes. especially dense non-aqueous phase liquids like TCE. Negligibly soluble and well below the odor threshhold at those concentrations. Just my opinion, again, I can’t science it other than my anecdotes.