Music, but Physical

 Music, but Physical

We hear things all the time, right? Soundwaves exist everywhere, and every now and then. Music instruments are associated with concepts of “frequency”, “energy” and some other physics terminologies. I don't hope to explain the terms in a classroom setting-- that's pretty boring. 😐 So I invite you to envision us at a disco party 🕺: we feel the loud music vibrating our bodies. The music and drum synchronize with our heartbeat, rendering us connected. We dance following the beat, or “soundwaves”! 😏 And that’s probably a few occasions where we feel soundwaves outside of the physics classroom. There is an interesting little experiment to do: Find a factory where there’s a pipe with water inside. If one knocks on the other side, we can hear the sound three times, because of the water, air, and solid transfer sounds at different speeds. As particles are more closely together in a solid, the vibration ENERGY (I know you hate that word) transfers faster. Easy to understand, huh? Applying the same concept to something we are all familiar with: "music" is simply composed of sounds of different wavelengths or frequencies. 

Switching to another related concept, "echos". Echo does take place all the time, but sometimes we cannot hear them, especially in a small, enclosed room. Let me do a simple calculation here. The speed of sound equals 343 m/s. However, a sound signal takes 0.1s to transfer to our brain to be really “heard” by us, meaning two sounds that take place within 0.1s cannot be identified as two sounds. 343m/s * 0.1s equals 34.3m. Thus, if there is room for a sound to travel 34.3 m and come back to our ear without being too dim to be heard, we hear an echo of the previous sound.

This is what we see in a theater, on the wall, devices are installed to reduce echoes by absorbing them. Essentially, the sound bounces to them without bouncing out again. By limiting echoes, the audience can appreciate the music without being disturbed. Mentioning an interesting fact here: you can hear the music faster in front of your phone during the live stream than in the back seat of the concert. Think about why :) 🎤📱