If sound travels better through solids than liquids, why do we cover the phone receiver with our hands?

Question

If sound travels better through solids than liquids, why do we cover the phone receiver with our hands?

Answer 1

the microphone inside any phone is very low quality, it can only pick up loud sounds, hence the reason why we have to shout if the phone is on loudspeaker, any blockage to the microphone, like a hand, really weakens the sound energy, and the microphone is too low quality to pick it up, personally i just press secrecy.

Answer 2

i would like to ask a question, kinda similar, and related

sound passes better through solids than liquids and air due to less atoms/ions to carry on the vibrations so why don't they leave air instead of putting a waal there in the first place?

my answer to the origional question is the hand creates a barrier so sound has to transfer from air to solid to gass again, slowing down the vibrations and then making them inaudible, somthing like that anyway

Answer 3

I dont i cover the phone Mic

Maybe this is where you're going wrong.

Answer 4

Sound doesn't travel better through solids than liquids. If you scream underwater and someone is 10 feet away, they can hear you. If you scream and there is 10 feet of concrete between you, then they are not going to hear you. If you cover the phone receiver with your hand, you will still be heard. Just not to the degree without the hand. Use the mute button.

Answer 5

To prevent sound waves that are traveling through the air (neither a solid or liquid) to make it to the microphone in the mouthpiece.

Answer 6

The phone would stop working if we covered it with liquid.

Answer 7

Sound travels faster through solids, but it's also dampened much more. We cover the phone receiver with our hands to shield it from the outer noises, and to provide a sound chamber for our voice.

Answer 8

Firstly, sound does not really travel 'better' through denser materials, e.g. solids and liquids. It simply travels faster. So by covering the phone with our hand, the sound has three 'choices.' Most of the sound is absorbed into your hand through energy transfer, being transformed mostly into heat. Some sound is reflected back off your hand, and may be absorbed somewhere else. And a small portion of the sound will go through your hand, so the sound is quieter, when you try to listen to it.

Answer 9

the CHANGE of the impedance of the medium (and so the speed of sound) makes some of the sound reflect, so it's not transmitted through

people match impedance to stop reflections and improve signals as outlined here

http://en.wikipedia.org/wiki/Impedance_m...

so yes sound travels faster through solids, but changes the medium are what causes the reduction in transmission

(impedance is analogous to the resistance of a DC circuit, (it means to impede or obstruct. [the signal in this case])  

with AC and waves in general, impedance can be dependant on the frequency.  An analogy you might be familiar with is light through glass.  Some of the light is reflected at the boundary (on entering and leaving the glass too), because of the change in refractive index (like impedance))

if you cant be bothered to read the link, the reflection is given by

Z2-Z1  /  Z2+Z1

where the Zs are the impedances of the materials (and may be dependant on the frequency of the signal)

so for sound going from air to water to air again, about 10% of the power gets through(i think) while the rest is reflected somewhere. your hand contains muscle and bone etc all with different impedances so even less would get through

as for extra 'damping' in solids or liquids, what about earthquakes or the sofar channel where the sounds travel hundreds of miles?!

Answer 10

You can try putting water in it if you like

Answer 11

hand creates a barrier so sound has to transfer from air to solid to gass again, slowing down the vibrations and then making them inaudible

Answer 12

the phone's reciever antenna doz not catch a mechanical signal it does actually recieve electrical signal (electromagnetic one)

so covering does not affect the reception of the signal....

Answer 13

tried the liquid thing but my phone not like it. by accident of course. good question