### Poetry at the Goat and Superhero Outfit Changes

This place is so cool!

I was sitting at the Hungry Goat tonight working on another tech book during the weekly poetry reading. I'm not sure if that's a cognitive dissonance or an oxymoron, but that's what I was doing. Actually it's probably neither, but I've always wanted to use the word dissonance.

Anyway! I was sitting at the front door working away. OK, I wasn't working. The trial version of Microsoft Office had expired and I was installing the new version, which was taking forever, so, umm... yeah... I was actually doing what I do best down here: watching the world go by.

So, getting back to the story, as I'm watching the world go by, (accompanied by ranting poetry in the background), a woman pulls up on a classic Vespa and parks on the sidewalk. She's got a bob haircut, and she's wearing a white leather jacket, pink tights, and a pair of white go-go boots. For all the world, she looked like she was going to do an interpretive dance to one of the poems. I smiled and got back to my very intense installation work, (watching the little green bar go across the screen).

About two minutes later, she comes back out. Except now, she's wearing heels, a sleek dress, and the white leather jacket. Apparently, the Goat is her Boulder phone booth. She laid the boots on the floor of the Vespa, (conclusively proving that yes, there is no crime in Boulder), and off she went to whatever it is you can do down the street with a nice dress, but not with pink tights.

Always something new here. And to think, I almost bought a TV!

### Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems, there seem to be fewer explanations of the procedure for deriving the conversion, so here goes!

What do we actually want?

To convert the Cartesian nabla

to the nabla for another coordinate system, say… cylindrical coordinates.

What we’ll need:

1. The Cartesian Nabla:

2. A set of equations relating the Cartesian coordinates to cylindrical coordinates:

3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system:

How to do it:

Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables.

The chain rule can be used to convert a differential operator in terms of one variable into a series of differential operators in terms of othe…

### The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1.  While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero.  This is typically explained in the following way.  While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare.  That doesn't stop us from looking for them though!

Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2].  Cabrera was utilizing a loop type of magnetic monopole detector.  Its operation is in concept very simpl…