How does physics apply to Ultrasound?

How do we use it in ultrasound?Anything is helpful. I'm using it to finish writing a physics paper.How does physics apply to Ultrasound?
This is a very ambiguous question so I will ask you one: how does physics NOT apply to ultrasound?





Here's something to chew over though, ultrasound is simply a very very high frequency sound wave, and we ALL know sound is transmitted by waves, right? Oscillitary variations in the density of a medium?





Wrong. Well, right until you start to consider the quantum mechanical properties of lattice oscillations in crystal structures. Technically, these are still sound waves but they are discribed as being a quantum particle called the phonon. More interstingly, in ionically bonded crystals, this phonon (sound particle) can couple with a photon (light particle) and exchange energy. The phenomenon is not at all rare, so read up on it. Ultrasound scans of crystals actually can cause the crystal to emit light.





That's physics.How does physics apply to Ultrasound?
Ultrasound is a sound wave that is above human hearing. We do not hear it, but it travels the same and reflects the same. It is used in medicine to see interanal parts without the use of harmful xrays.It applys to physics because it is a longitudinal wave and behaves according to wave theory.
well physics apply to EVERYTHING ( sound waves and harmonics - density and reflective properties of materials and on and on ----not to mention the transducer and the receiver )





this might not be the best example of applied physics - if you take it to it's simplest form ultrasound is little different from hitting a piece of metal with a hammer and judging it's condition by listening to the sound it makes ( LOL ) maybe you should try X-RAYS





just as an aside - we mostly hear about medical Ultrasound but it's primary use is in materials testing ( it is non-invasive and can detect internal flaws in metal where X-rays are impractical or impossible