C Major Scale

Sorry, I don't remember how to rotate videos :( I guess the sound is the most important part though. Anyway, this is what a C major scale on a cello sounds like, though preferably more exactly in tune. I've been wanting to write a blog about the cello for a while now, and since we are currently learning about sound, it seemed like the right time. With most string instruments, a bow is pulled across the strings, which vibrates them and produces sound waves. The strings with a smaller diameter produce a higher sound and therefore waves with a greater frequency. The strings with a larger diameter produce a lower sound and therefore waves with a lower frequency. In orchestra everyday, we tune to an A with a frequency of 440 Hz. Some orchestras tune to an A with higher frequencies, but 440 is the most common. When string players tune, they either tighten the strings, which yields a higher pitch, or they loosen the strings, which creates a lower pitch. When string players place their fingers on the strings, it shortens the length of the string which produces higher notes of greater frequencies.

From the lab that we did on Friday, we learned that when you play a note and then move twelve half steps up, the frequency doubles. If you move twelve half steps down, the frequency halves. To apply that concept here, the second C that is played has a frequency two times that of the frequency of the lowest C, the third C played has a frequency four times that of the frequency of the lowest C, and the fourth and highest C played has a frequency eight times that of the frequency of the lowest C.

Dance Showcase

Last night, I went to dance showcase, so that's what I decided to write my blog about. Sorry about all of the heads. This is a video of a hula that uses pu`ili. There is so much physics in dance, but I'll just mention a couple concepts. As you can see, there are a lot of turns in this particular dance. The friction between the dancers' feet and the ground allows the dancers to pivot and turn. If there was no friction, their feet would just slip and they wouldn't be able to pivot. In this dance, the dancers also tap themselves with their pu`ili and tap their pu`ili against each other. They don't want to hit themselves too hard, so they have to make sure that they don't apply too much force!

This is a video of two of my friends chanting. It is really short because my camera ran out of memory :( Anyway, as we are just beginning our study of oscillations and harmonic motion, this video becomes more relevant. The sound of their voices travels in waves across the gym. My friend Pua, who is on the left, has a higher voice than my friend Daiva, who is on the right. This means that the sound waves the Pua produces have a higher frequency than the sound waves that Daiva produces. However, in this case, their frequencies should be the same since they are theoretically chanting at the same pitch. In the first video, you can also hear the music that the dancers are dancing to. My friends would both kill me if they knew I was using these videos for my blog :)