research April 8, 2014

Beats by Me

By Jenny

MAD Day is the annual day where Caltech students get together and get mad.

Just kidding. It’s actually quite the opposite in some senses. MAD stands for Make-A-Difference, and it’s something that the Caltech Ydoes to promote campus-wide community service. To read more about the Caltech Y, check out Laura and Wen Min’s blog (What? The Y? Why?).

My friend, Nelson, and I lead a trip out to Trash for Teaching(T4T), an organization that collects junk from large corporations and anyone else and keeps it for teachers who want to use the materials for classroom projects to teach science. We were fortunate enough to be there as the T4T folk were training a group of enthusiastic and dedicated local physics teachers. (My heart cries out of gratefulness for them–they were there for most of that Saturday!)

Look! Isn’t this just beautiful? It’s the DIY-soul’s treasure island. (:

The project of the day was headphones. That’s right. We made actual headphones out of these reused materials and learned some physics while we were at it! (I’m terrible at physics, but this made it so applicable andreal! Thanks, T4T!)

One of Aaron’s headphones.

The physics was actually pretty simple. Here’s How to Make Headphones 101 if you’re ever bored:

Glue a magnet to the bottom of a bottle cap. It’ll provide a magnetic field.
Coil a naked wire 50 times around a small roll of cloth so that it fits on your pinky.
Place the coil on the magnet. Make sure the coil is taller than the edges of the bottle cap.
Cover the bottle cap with a piece of membranous material that’s a little stretchy. Let the ends of the wires peek out. Make sure the membrane is stretched kind of tight like the top of a djembe.
Attach each wire to an alligator clip from this kind of adapter with an audio jack on the end(actually I’m not sure if this is exactly it, but it looks close heh). The idea is that the music from the audio jack will be split into the two wires, which, when connected to your two wires, will generate the current that produces the sounds. That current going through the wire will generate its own magnetic field because physics.
The coil of wire will move in reaction to the force from the two magnetic fields fighting, which will cause the tight membrane to vibrate, giving you the sounds that reach your ear! (:

Kevin’s creation.

There are more pictures hereas well as the ones from previous years of MAD Day, but in short, it was a great and refreshing experience for us all and none of us came out of it mad, I promise!