Question

tip of the day- when we take a dip then if we shout or say something inside the water then our voice will not come outside of the water surface you know why because of total internal reflection phenomenon.

Answer 1

oh cool. i thought only light undergo total internal reflection :)

Answer 2

@cherrydrops-hahah yes in some cases sound wave also follow coz wave is common term between light and sound

Answer 3

nice! :)

Answer 4

interesting but i don't think thats true.. cause u are missing out one important factor buddy

light travels faster in air and slower in water.. and thats why.. when light goes from water to air.. there is a chance of breaching critical angle and hitting total internal

what about sound? well yea.. sound can undergo too.. it obeys snells law too but

SOUND TRAVELS faster in water.. than in air.. so won't that make a difference?!

Answer 5

so if anything it should happen when sound goes from AIR to water..

so when u are inside water, you may not hear sound from the outside world..

Answer 6

ya speed also matter .if u talking about air to water interface then no TIR will occur coz for TIR light should pass from denser to rarer medium.

Answer 7

@08surya I have to side with @Mashy if there are sides (even though I don't like sides).

Experimental results show otherwise. That is, I can scream underwater and be heard above water. Also, I can be underwater and hear noise from the air.

There is one main issue I see, even though I'm not quite adept with all of this.
Most single sound sources produce sound in nearly all directions, because that is the natural tendency of sound. Therefore, there will be many angles, and total internal reflection does not apply to all of them.

Answer 8

@theEric -i have also notes what i said about sound wave

Answer 9

Your notes say that sound cannot escape from water? But I've experimentally proven otherwise. Unless my memory is wrong, or misinterpreted.

Has anyone else heard sound source from underwater?

Answer 10

Has anyone else heard sound sourced from underwater?*

Answer 11

i never said sound can not escape through wate. isaid human voice is not capable to escape through water. coz intensity of sound is low and TIR takes place

Answer 12

Ah, I see. I guess that can be proved! And my memory is probably just incorrect, if that is the case.

Hehe, I might repeat the experiment next summer to be sure! Or maybe if I swim in an indoor pool.

Answer 13

do ur experiment in deep water and then pls tell me

Answer 14

How deep does it have to be?

Also, does the angle from which somebody listens matter? I mean, even if the sound is emitted straight up only (which would be inaudible), the air would then diffuse the sound in nearly all directions, right?

And the sound would compete with the sound from the bubbles.

I really hope I remember this post when I try it.

Answer 15

i dont think u r keen to listen my thoughts .....so m not going to xplain again.i know m not wrong thats it

Answer 16

Okay... I heard the concept - total internal reflection in water to air of the frequencies produced by the human voice. I don't know how it works! I just wanted to contribute my information - that I think I have heard voices from underwater.

Like I said, my memory might be incorrect! Given that this is proved, which is highly probable because you learned it in class, then it is probably my memory that is mistaken. I could be remembering hearing the noise from underwater. Or maybe it is just that I remember hearing sounds from outside the water while I was in the water.

At any rate, I still want to experiment again... Never hurts to revalidate physics.

Answer 17

really sry if i hearted u.and whatever i think if ur eperiment is right then concept of TIR doesnot eist and due to that we should search what is going in optical fiber coz many theories said it is due to TIR

Answer 18

Try to think of it this way

when sound goes from water to air.. then it speeds down.. now if u used a ray diagram to depict that.. then u would see that the ray of sound would bend TOWARDS the normal.. how can you possible expect it to TIR back into water? :P..

Answer 19

OK @Mashy what u want to say pls give a straight answer is it possible or not?

Answer 20

well i think its not possible.. the reverse might be true.. from air to water..

Answer 21

what air to water is possible

Answer 22

TIR of sound

Answer 23

in case of air to water there is no TIR so refraction is another thing so some sound will go inside the water and it is audible or not it will depend to position and intensity of refracted sound...

Answer 24

i would like to tell one thing for TIR sound or light should pass through denser to rarer medium ...respect to water air is rarer so TIR is not possible

Answer 25

when we use the word density here.. it doesn't really mean the density as in kg/m^3

example for light.. density is optical density.. we say optical density is high if the light travels slower..

similarly we can say acoustic density is high if sound travels slower

so to apply snell's law and talk about density we will now have to think of acousitc density.. so by that definition.. acoustic density of water is smaller than that of air!

Answer 26

long disscusion for this question thnx @Mashy and @theeric

Answer 27

no problem.. i hope you got my point :)!

Answer 28

i m not saying my concept for water to air is wrong .....ya your point is somewhat true for air to water

Answer 29

do you have any websource you can link me to? cause i can't find anything over the net that says sound goes TIR from water to air

Answer 30

see this one also agrees with me :P

http://answers.yahoo.com/question/index?qid=20071204172340AA0pELW

Answer 31

my sessional xam is going on after am i will try to find if i find it then i will inform u

Answer 32

oki :) :).. then you better continue studying for your sessionals.. r u doing tronics?!

Answer 33

thnx.yup

Answer 34

cool even m a tronics graduate :D

Answer 35

which university n where r u presently

Answer 36

some local university in mangalore :D :D.. now m a physics teacher..

Answer 37

my fav subject.where r u doing your job

Answer 38

In mangalore itself! i teach pre university!

Answer 39

great

Answer 40

oki now i gtg see ya!

Answer 41

bye

Answer 42

No matter what, this post was a great discussion! :)

As for me, I still don't know if I should trust my memory or not. :)

Take care! Good luck on your exams, @08surya!

Answer 43

@theEric -thnx