Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: mriver8 on 07/10/2014 04:14:30

Title: Is ultrasound traveling on a direct path affected when entering an area where?
Post by: mriver8 on 07/10/2014 04:14:30

it crosses paths with sound waves within the normal hearing freq range?

Title: Re: Is ultrasound traveling on a direct path affected when entering an area where?
Post by: alancalverd on 07/10/2014 07:58:06

Since sound is reflected at the interface of differing elasticities, and since the elasticity of an inhomogeneous medium varies with pressure, it is in principle possible to map a standing wave of low frequency in, say, a biological medium, with ultrasound.

The conditions for doing so are, alas, beyond the capability of the CIA: if they want to know whether you are listening to communist music or plotting the downfall of the Bilderberg-military-industrial complex, they will have to use a microphone, just like everyone else. Or they could just ask you, but where's the fun in that? Aliens use an anal probe. 

Title: Re: Is ultrasound traveling on a direct path affected when entering an area where?
Post by: syhprum on 07/10/2014 08:08:59

I often wondered what the object of all the anal probing was that is inflicted on those abducted to alien UFO's , now we know

Title: Re: Is ultrasound traveling on a direct path affected when entering an area where?
Post by: mriver8 on 07/10/2014 10:36:51

Quote from: alancalverd on 07/10/2014 07:58:06

Since sound is reflected at the interface of differing elasticities, and since the elasticity of an inhomogeneous medium varies with pressure, it is in principle possible to map a standing wave of low frequency in, say, a biological medium, with ultrasound.

The conditions for doing so are, alas, beyond the capability of the CIA: if they want to know whether you are listening to communist music or plotting the downfall of the Bilderberg-military-industrial complex, they will have to use a microphone, just like everyone else. Or they could just ask you, but where's the fun in that? Aliens use an anal probe.

You aren't answering my question which is do soundwaves traveling on two seperate but direct paths change course if they cross eachother's path. To put it simpler wpuld blasting the stereo in an ultrasound room at an extremely loud volume affect the testing at all?

Title: Re: Is ultrasound traveling on a direct path affected when entering an area where?
Post by: alancalverd on 07/10/2014 11:58:05

Pressure waves do indeed interfere, and a sufficiently intense low-frequency pressure wave in an inhomgeneous medium will modify the ultrasound image of that medium. Which is exactly what I said above. In the case of medical ultrasound the US probe is held in contact with the patient's surface and the insides of the patient are subject to all sorts of compression and movement anyway if he is alive. You might just be able to detect a 5 - 10 kHz standing wave in a liver with a 100 kHz ultrasound probe.