Scrutable

The weird sonic effects of ice cracking.
https://youtu.be/92gkjqISi38 - could also be in the 'best shorts'

A long time ago I heard a similar effect during a winter freeze when someone was throwing stones onto a frozen canal.


ETA - my assumption is that it's because some sound propagates through the ice and some through the air - but each at different speeds.

Gfamily wrote: ↑

Tue Feb 09, 2021 12:13 am

The weird sonic effects of ice cracking.
https://youtu.be/92gkjqISi38 - could also be in the 'best shorts'

A long time ago I heard a similar effect during a winter freeze when someone was throwing stones onto a frozen canal.


ETA - my assumption is that it's because some sound propagates through the ice and some through the air - but each at different speeds.

I guess the maths of how different frequencies propagate in the different media probably shares something with optics, ie we are hearing the analogue of chromatic aberration. Shpalman and dyqik are probably qualified to comment on my guess.

basementer wrote: ↑

Tue Feb 09, 2021 3:57 am

Gfamily wrote: ↑

Tue Feb 09, 2021 12:13 am

The weird sonic effects of ice cracking.
https://youtu.be/92gkjqISi38 - could also be in the 'best shorts'

A long time ago I heard a similar effect during a winter freeze when someone was throwing stones onto a frozen canal.


ETA - my assumption is that it's because some sound propagates through the ice and some through the air - but each at different speeds.

I guess the maths of how different frequencies propagate in the different media probably shares something with optics, ie we are hearing the analogue of chromatic aberration. Shpalman and dyqik are probably qualified to comment on my guess.

I remember doing phonons in solid state physics before electrons but I don't really remember much of it.

It reminds me of the sounds you hear when the vibrations of an approaching train reach you via the rails (or overhead wires).

The effect (wave velocity* depending on frequency) in general is called "dispersion" by the way.

https://silentlistening.wordpress.com/2 ... ce-sheets/

(* - yes I know there are two kinds of velocity)

It's curious that the ice was visibly cracking and making all that noise when it appeared to be frozen to a considerable depth. Maybe the impression of thickness was an illusion caused by the wide angle lens, IDK.

But the noises were very familiar. I used to do curling and the experience of playing on a lake is very different to a rink. First rule of lake curling is you don't tidy all the stones neatly together between ends. Second rule of lake curling is when the ice starts making all those sonar noises you remember rule 1 and spread the stones apart f.cking pronto.

I've never been on a frozen lake and if it started making those noises I'd get off it pretty quickly.