### Daybreak and Real Physicists

The new AT&T internet serial Daybreak is awesome! I watched the first three episodes last week after I heard about it from the Chief Engineer of the New Yorker Hotel. The story, so far about a race to find one of Nikola Tesla's lost inventions, portrays physicists in an exciting light if nothing else. But is it real? Here's a check of how the physicists in Daybreak compare to real life physicists. Since I'm not too bashful, I'll serve as the real life physicist, (well physics student).

Do Physicists Really Live in Trailer Parks?
DaybreakReal Life

Of Course they do! Have you ever checked rental prices near Brookhaven National Laboratory? Ideally, your trailer should fit easily behind your car so you can move from laboratory to laboratory with ease.

Do Physicists Drive Motorcycles?
DaybreakReal Life

Yup! Although ours tend to be wired for data acquisition.

DaybreakReal Life

They do! You have to have a home base. It should be noted though that the barrels are for making the wood burning heaters that are essential for cold desert nights.

Do Physicists Really Own Pea Green Double Ovens?
DaybreakReal Life

As it turns out, desert hideouts don't come equipped with great ovens. However, if you've got \$20 and you watch craigslist, you're all set.

DaybreakReal Life

Might I direct you to the masthead for this blog? We're all about shiny dials! The masthead photograph was taken during a tour of the basement of the New Yorker hotel. More about that later... I don't want to give too much away.

### 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…

### Lab Book 2014_07_10 More NaI Characterization

Summary: Much more plunking around with the NaI detector and sources today.  A Pb shield was built to eliminate cosmic ray muons as well as potassium 40 radiation from the concreted building.  The spectra are much cleaner, but still don't have the count rates or distinctive peaks that are expected.
New to the experiment?  Scroll to the bottom to see background and get caught up.
Lab Book Threshold for the QVT is currently set at -1.49 volts.  Remember to divide this by 100 to get the actual threshold voltage. A new spectrum recording the lines of all three sources, Cs 137, Co 60, and Sr 90, was started at approximately 10:55. Took data for about an hour.
Started the Cs 137 only spectrum at about 11:55 AM

Here’s the no-source background from yesterday
In comparison, here’s the 3 source spectrum from this morning.

The three source spectrum shows peak structure not exhibited by the background alone. I forgot to take scope pictures of the Cs137 run. I do however, have the printout, and…

### Unschooling Math Jams: Squaring Numbers in their own Base

Some of the most fun I have working on math with seven year-old No. 1 is discovering new things about math myself.  Last week, we discovered that square of any number in its own base is 100!  Pretty cool!  As usual we figured it out by talking rather than by writing things down, and as usual it was sheer happenstance that we figured it out at all.  Here’s how it went.

I've really been looking forward to working through multiplication ala binary numbers with seven year-old No. 1.  She kind of beat me to the punch though: in the last few weeks she's been learning her multiplication tables in base 10 on her own.  This became apparent when five year-old No. 2 decided he wanted to do some 'schoolwork' a few days back.

"I can sing that song... about the letters? all by myself now!"  2 meant the alphabet song.  His attitude towards academics is the ultimate in not retaining unnecessary facts, not even the name of the song :)

After 2 had worked his way through the so…