Why does Sound Travel Better with the Wind?
You may have noticed that you can hear a sound better if it comes from downwind rather than upwind. We assume that this is because the wind “pushes the sound along.” Unfortunately for our intuitions, it can easily be shown that this force is too small to account for the observed effect. The speed of sound in air is about 760 miles per hour (1223 kph). If a typical wind is blowing at 30 mph, this is only four percent of the speed of sound, meaning that wind can only shorten or increase the distance a given sound needs to travel by that amount. The difference in sound would be too subtle to be detected by the human ear, so obviously this does not uncover the source of the phenomenon. The actual solution is attached to a property physicists called viscosity. Due to viscosity, wind velocity near the ground is actually slower than velocity at higher altitudes. Collisions between air molecules and the ground give rise to turbulence effects which prevent waves from being transmitted along thi
