A guest post by Dante.
Wonderful Freeman invited me to write up a math/computer science post, and so here it is. Math seems like common sense, and if you only think of it you can understand it. So here is a little puzzle you can think about to explain a common phenomenon: why is it that if you are in a shower, or on a treadmill, it's really hard to hear someone call out to you, even though they can hear you.
I have three (impulsive) boys, and as such I encountered this often. The answer is pretty simple, and with a couple of concepts, you can puzzle it out for yourself.
The first concept is Signal to Noise Ratio (SNR). Here, voice is the signal, and noise is anything generating sound that isn't part of the signal (like the shower or treadmill). In general, to decipher a signal, it has to be stronger than the noise. How much stronger isn't too important for the concept part of it.
The next concept is that over distance, sound (noise or signal) decreases in strength.
With these two concepts, you can use common sense to figure out what is going on.
