Question from Mandy: I heard a guy on the radio say you can hear the difference between hot running water and cold running water.
That sounds absolutely crazy to me. Is it true?
Rick’s answer: The short answer to your question is yes, Mandy.
You really can hear the difference between hot and cold running water.
In fact, it’s quite easy for a person with somewhat normal hearing to discern the difference in the sounds made by hot and cold running water just by listening to it.
And this is actually very easy to verify by performing a very simple experiment…
Simply turn the hot water in your shower all the way on and leave the cold water off, then listen to the sound the water makes as it exits the shower head and strikes the shower floor.
As the water begins to warm up you’ll begin to hear a change in the sound the running water is making.
After the water is completely hot you’ll hear a sound that’s completely different from the sound you heard while the water was still cold.
If you’re wondering why the temperature of running water affects the sound it makes, it all comes down to everyday physics…
As water (or most any other liquid) heats up it becomes less viscous – meaning it becomes thinner.
This is the reason we heat syrup in a microwave to make it easier to pour onto our pancakes.
As you’ll find out when you perform the “shower” experiment described above, the viscosity (i.e. thickness) of water affects the sound it makes when it’s running.
Want to see a similar experiment in action right now?
Watch the short video below and listen to the difference between the sounds of hot and cold water as they are poured from a pitcher into a cup.
Note: As always, you can watch the video at full screen by clicking the “square” icon that will pop up in the lower-right corner of the video after it begins playing.
Pretty cool, right?
Now you know how to tell the difference between hot and cold water simply by listening to the sound it makes while it’s running!