Noticed it today, rather than a gradual build up of noise you just suddenly hear an airplane like it appeared out of nowhere?
In: Physics
There are lots of great answers hear. Another factor is our brain is great at filtering background information like sounds. All day long we get inundated with noise and we don’t *really* notice it moment to moment. Our brain stops us from devoting energy to it since we don’t need to deal with it. So an airplane engine is just muted by our brain until something sets it apart. Might be that it crossed a sound level threshold, might be a different sound pitch than normal, etc. If you ever get out in the wilderness without noise around ( I live in a desert) you can hear airplanes much farther away than you think you could because your sense of hearing can focus on the sound.
Latest Answers