How do we hear multiple sounds when it’s just one air vibrating?

Question

Like for example when I’m listening to an orchestra I can hear a clarinet and a violin quite distinctly from one another, but they’re both sounds vibrating through the same air. Logically, shouldn’t one air only be able to carry one frequency (Vibrate in only one way)? How does the air contain so many frequencies simultaneously?

In: 80

Answer 1

Look at this video because it’s a visual example of your question

around 0:20 you can see on the right side a low energy small circle shaped waves with high frequencies. On the center you can see the big and main intense ripple that is approaching from the center of the frame. The small waves remain on their way and so the big one does, as they are transparent and independent to each other, and no wave interact with another wave. That’s called interference of waves.

Waves are like “asocial”, they don’t care of other waves. It’s pretty surprising, isn’t it ? still blows my mind that each wave seems completely independent to each other. Pretty much the same happens on that video happens on air.

The medium is one the water, only the same medium, same as the air. So how toes it happens?

A good way to try understand it is with kinetic theory, molecules of air move randomly in all direction and collide with others. In silence its all homogeneous. but if we create a wave (an instrument does) it creates it’s own pattern of “more than average” and “less than average” density of particles. Because there is a incredible big amount of air molecules, some of them by chance may be more influenced by the pattern of the violin and others will follow the influence the pattern of the clarinet. There is particles enough for each instrument patterns so both instrument will propagate.

The other part about how our ears and brain did the evolution to have a short memory buffer to distinguish patterns and enough accuracy to differentiate those patterns i think it may be related to survival ability. Like distinguish the rain noise from a mosquito from the sound of a predator coming. The latter is more dangerous.