How can we tell something (like sound) is a wave if it is invisible or too small for us to see?
How do musical instruments work?
What's the difference between a woodwind & a stringed instrument?
This week in Physics, we learned all about sound waves and harmonics. We did a lab in which we analyzed closed end pipes that produced musical notes.
We started the lab by measuring the palm pipe's length and diameter. We then used these measurements to find wavelength, frequency and ultimately, the musical note the pipe would produce.
Here are my calculations:
length of the pipe: 15.8 cm (.158 m)
diameter of the pipe: 1.4 cm (.014 m)
1) Length= 1/4(wavelength) - 1/4(diameter)
.158 m = 1/4(wavelength) - 1/4(.014 m)
wavelength= .646 m
2) Velocity= frequency x wavelength
343 m/s = frequency (.646 m)
frequency = 531 Hertz
I then plugged in this information to Wolfram Alpha and found out that my pipe produced the C5 note and 25 cents. After everyone figured out their notes, as a class, we harmonized in playing Twinkle Twinkle Little Star. Not going to lie, we were pretty darn good. America's Got Talent worthy? I think yes!
Since everyone at our table had different size pipes, we figured out that the different lengths created different notes. The longer the pipe, the lower the note and the shorter the pipe, the higher the note. This is because, since only odd numbered harmonics can fit in closed end pipes, longer waves can fit in a longer pipe, therefore creating a lower note.
Real World Connection:
Learning about harmonics in class is really cool because music is something we listen to in our daily lives, and getting to relate something we love to something we learn in school is so cool. It's awesome to actually understand how music is created! Seeing how awesome we were at "Twinkle Twinkle Little Star" made me wonder if people play the "PVC Pipes," and guess what... THEY DO! This video shows a guy playing "The Legend of Zelda" on his very own set of PVC pipes. I bet if our class practiced enough, we could totally play bigger and better things than "Twinkle Twinkle" (not that it's not a classic).
By the way, this kid is great!
Imagine putting our whole class's pipes together and creating a complex PVC pipe instrument like this! It's all Physics!