Sound travels further in cold weather (2019) | Hacker News Reader

Sound travels further in cold weather (2019)

blog.weatherops.com

32 pointsredtriumph24 comments

It does indeed.

It's now cold in Kiev and the sound of russian missile explosion just an hour ago was the loudest I've heard so far despite not being outside.

.. even further (and faster) in hot - not because of temperature - but because of its inversion (which happens as well in Africa -> Atmospheric controls on elephant communication).

Air acoustic impedance vs temperature is 403.2 Pa·s/m at 35°C and 449.1 Pa·s/m at −25°C ( https://en.wikipedia.org/wiki/Density_of_air ).

Air absorbtion/attenuation (because of molecular relaxation..) is a function of temperature, humidity and sound frequency - at 8kHz and humidity: 10% - max at 33°C min at 12°C then grows, 40% - max at 18°C, range .25-5dB/100m (and can be neglected if not for long distances and high frequencies) ( https://www.sfu.ca/sonic-studio-webdav/handbook/Sound_Propag... ).

I also wonder if leaves on deciduous trees muffle the sound after winter.

They do, I notice the effect in my area every year. In summer I can't hear the traffic on a highway a mile away, in winter I can hear it. Insects and birds make noise in summer also, which raises the background noise level.

It never ceases to amaze me that light (the fastest and most powerful thing in our universe) can be easily blocked whereas sound, being less powerful and slower, is more penetrating. We can close the blinds/curtains and have total darkness, but try completely blocking the sound from the neighbors in such a simple way, impossible :-)

All you need is a bit of hard vacuum in between, even micrometer thick layer is enough. Now how to do it continuously without joining parts is a bit of challenge now

That is because light is a particle itself whereas sound is potential energy cascading through matter

Ah yes. Iv'e long strongly, strongly suspected either it has to do with cold weather, or that it's dependent on inversion which is most likely during cold weather.

I've heard trains that are usually only heard a coupld of hundred meters suddenly being audible from several kilometers away during cold winter mornings. Same with aircraft taking off from the local airport.

"Sound travels more efficiently through denser materials" is pretty well accepted and colder air is denser. Wait til they learn about elephants listening with their feet or whales talking across huge distances.

I was surprised to hear that sounds travel faster in thinner, warm air however.

For the first not so easy - what about soundproofing ? (For sound to be able to vibrate through an object, the object itself must be able to vibrate. This is why extremely dense materials make for great soundproofing as they are too thick to vibrate. Mass is a fairly straightforward soundproofing principle — the greater an object’s mass, the harder it is for sound to shake the object or push through.. - colder air is heavier, so energy (even if more ..or regardless(?) of transmission (into..?) ) to shake it shall last for shorter distance - right ?)

About the second: When air is colder, the molecules are closer together, so sound transmission should be easier. This is true of solids and liquids, but gases behave a little differently. When gases heat up, their molecules move much more quickly. This increased vibration transmits the sound more quickly than it would in colder, but more static, air. ( https://www.soundproofcow.com/sound-travels-different-materi... )

That sounds a bit odd. Sound is coherent motion of the conducting medium, whereas motion of gas molecules is random. I always associated the increased speed with reduced density, and hence reduced "inertia" with increasing temperature.

This is a bit off... Sounds are detectable farther away in cold weather. Hot weather introduces more background static and thus signal is scattered and buried more efficiently.

That also sounds off because you're putting it as if yours is the only effect; don't you still have to combine what you say (less background noise, if I get it correctly - I do wonder about what SPL levels you're talking about here, and in any case they will be orders of magnitude smaller than sound produced by a train for instance, so does that noise still matter than?) and what the article says (inversion)? tldr; please elaborate, preferably with references.

Sound travels farther in cold weather. FTFY

That's not fixed at all, that's an opinion; the dictionary (several) says either is fine.

There is no final, undisputed arbiter of what is right and proper in English, no Academy of English, no written law. Maybe there is consensus within a social group, nation, or profession, but a whole lot of these things are not provable.

Less/fewer is another one where people pipe up and claim one is "correct" (again, according to whom?), when in actual fact, either is fine and no-one cares and it's not provable either way.

Most sites that weigh in on this topic agree that "further" does not apply to physical distance. [0][1][2]

[0] https://www.merriam-webster.com/words-at-play/is-it-further-...

[1] https://www.grammarly.com/blog/farther-further/

[2] https://www.britannica.com/dictionary/eb/qa/what-s-the-diffe...

And yet they're arguing with themselves.

https://www.merriam-webster.com/dictionary/further

"Farther and further have been used more or less interchangeably throughout most of their history,"

""" A polarizing process appears to be taking place in their adjective use. Farther is taking over the meaning of distance the farther shore

and further the meaning of addition. needed no further invitation """

That, of course, means all of this is new and in no way "correct" by any current modern standard. It's just something quasi-literate internauts like to quip in the comments. Oh, and university style guide authors and editors who consider themselves authoritative, but to whom no-one except community college English teachers defer.

Maybe I'm a little bit of a linguistic anarchist, I don't know.

It sounded off to me. The thread was useful.

I'm not sure which side will prevail here. It isn't especially relevant to my usage.

my niece has her GCSEs coming up this summer, this information is going to put her at ease, let me tell you. :)

Unless there's been a recent significant snowfall.

The hush after a heavy snow is palpable.

Sound travels further in cold temperatures.

Sound travels further through cold air.

Do you have any reference for this ? The article says nothing about that. It says that sound travels further in a channel of cold air between warmer air and ground (it could be water even better).

I think it's the opposite: in lower temperature the air density is bigger and it's mass so energy to move the same mass shall exhaust (heat) at shorter distance..

The speed of sound is the square root of a modulus over the density where the modulus for a gas is the bulk modulus. The funny thing with vibrations is that it is not the density that primarily determines the change in speed of sound, but actually the modulus. Both typically change with temperature, however, the change in modulus is typically larger than the change in density and hence it dominates.

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