Does humidity affect how well sound travels?

Answer 1

Thanks for the questions.

First, we should be clear on what "how well sound travels" means for sound. I am taking it to primarily mean that the speed of sound is higher for the specified conditions. An alternate perspective which could require different explanations is from the view point of how far sound carries.


Humidity in the air makes the air lighter, less dense. This is because a molecule of water only masses about 18 atomic mass units, while air is about 29 AMU, which is an average
between the molecules of nitrogen (28) and oxygen (32). Airplane pilots know that when the humidity is high, it takes longer for them to lift off a runway because the air is less dense. This is also why low air pressure, (a falling barometer), means a storm is on the way, because of all the moist air of a storm being lighter than plain old dry air.

The presence of water vapor (humidity) in the air lowers the average mass of the molecules that are in the air. This has the effect of increasing the speed of sound in the air.

So I conclude that cold air should make sound travel slowly, while humid air should decrease the density of air, and also make sound travel faster.

Regards and Best Wishes

Answer 2

DanE summed it up QUITE thoroughly! Interesting stuff. Yes, sound DOES travel further in moist air...ever notice how much further you can hear in the fog? I'm PRETTY sure this gets canceled out when the humidity reaches 100% and it starts raining, I'm not sure why...(care to comment, Dan?).

Answer 3

I don't know to be honest and that is a good question e-mail me your answer when you find out ([e-mail]). Sorry I couldn't help you I try not to answer questions if I don't really know the answer,but this cought my attention.

Answer 4

Yes, both the velocity and the absorption change.

Answer 5

http://www.rane.com/pdf/eespeed.pdf