### Share QSO Maps!

The QSO mapper at http://copaseticflows.appspot.com/newqso now provides sharable QSO maps! Just enter the callsigns from your QSO:

Click the Map It! button and notice the sharing toolbar:

Choose the social site you'd like to share your map on, Facebook for example, and click that button on the sharing toolbar. You'll be asked for a comment for your map link:

Want a link without using another site like Facebook? Click on the 'Map Link' under the sharing toolbar to go directly to your map.

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

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics 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

### More Cowbell! Record Production using Google Forms and Charts

First, the what : This article shows how to embed a new Google Form into any web page. To demonstrate ths, a chart and form that allow blog readers to control the recording levels of each instrument in Blue Oyster Cult's "(Don't Fear) The Reaper" is used. HTML code from the Google version of the form included on this page is shown and the parts that need to be modified are highlighted. Next, the why : Google recently released an e-mail form feature that allows users of Google Documents to create an e-mail a form that automatically places each user's input into an associated spreadsheet. As it turns out, with a little bit of work, the forms that are created by Google Docs can be embedded into any web page. Now, The Goods: Click on the instrument you want turned up, click the submit button and then refresh the page. Through the magic of Google Forms as soon as you click on submit and refresh this web page, the data chart will update immediately. Turn up the:

### Law of Cosines and the Legendre Polynomials

This is so cool!!! A few days ago I extolled the virtues of the law of cosines, taught in high schools the world over, and claimed that it turned up in all kinds of problems that you run into later in physics.  I gave one example of an electrostatics problem I was working on, but I had a nagging feeling in the back of my head that there were even cooler examples I'd forgotten about.  It turns out that there is a way cooler example of the importance of the law of cosines!  The law of cosines can be used to calculate the Legendre polynomials!!! OK, so what are the Legendre polynomials?  They turn up repeatedly in graduate physics classes.  First of all, they're used to solve electrostatics problems [4].  The most noticeable place I saw them was in quantum mechanics, where they were derived as a special case of spherical harmonics.  Spherical harmonics are used to describe the wavefunction of an electron in a hydrogen atom, and ultimately to come up with graphs of the wave fun