Sense of sound and Mechanical Engineering.

I am a Mechanical Engineer. So I like to think that everything that happens in this world can be explained with Mechanical Engineering or Mechanical Engineering plays an important role in everything that happens around us. (I sometimes conveniently convert physics into Mechanical engineering while thinking of a problem and tell friends, see being a Mechanical Engineer I can solve this problem :))

Anyway, sometime last week, I was reading Modern Compressible Airflow by John D. Anderson, for understanding some things about shock waves and compressible flows in general when I came across this wonderful paragraph in that book, which I thought I should share.

"As you read this page, look up for a moment and consider the air around you. The air is composed of molecules that are moving about in random motion with different instantaneous instantaneous velocities and energies at different times. However, over a period of time, the mean molecular velocity and energy for a perfect gas can be defined as a function of temperature only. Now assume that a small firecracker denotes nearby. The energy released by the firecracker is absorbed by the surrounding air molecules, which results in an increase in their mean velocity. These faster molecules collide with their neighbors transferring some of their newly acquired energy. In turn, these neighbors collide with others resulting in a net transfer or propagation of the firecracker energy through space. This wave of energy travels through air at a velocity that must be somewhat related to the mean molecular velocity, because molecular collisions are propagating the wave. Through the wave, the energy increase also causes the pressure to change slightly (also density, temperature). As the wave passes you by, this small pressure variation is picked by your eardrum and is transmitted to your brain as the sense of sound."

Call me insane for this, but this description of a sound wave is insanely beautiful!!!