### The Look

Every so often it happens, someone asks how unschooling is working while giving me the ‘surely they’re done with that by now’ look. Sometimes the look gets to me, and gives me pause to think about whether what we’re doing really does work or not. Then, I remember where the kids really are academically, almost universally ahead in my opinion, and I relax a bit.

Annoying as it is the ‘look’ winds up being a positive force in general. It makes me re-evaluate my goals for unschooling in the first place. I just have two of them.  The first is  for the kids learn in a natural easy way that echoes the way I learned things growing up.   The second is for them to get out into the world to experience it, and to build the skills necessary to work with it.

Sometimes when I review, I realize we could focus more on one or the other of those goals, and try to amplify my efforts accordingly.  For example,

• “No. 1 mentioned she wanted to learn to solder, we need to take time to make that actually happen.” or
• “No. 2 is starting to bounce off the walls in the afternoon. He’s really good at action oriented activities like hikes and sports. I need to make dinners that we can take with us so we can walk out the door in the afternoon and hang out in our forested park or the playground instead of our house.” or
• “I noticed the kids are saying bye without making eye contact while leaving places we visit. We should start practicing role-play about greeting people when we’re out and about again.”

The look reminds me to do little things that make our unschooling life more effective and more fun, so, I’ll take it. Little reminders always help.

About the Antelope: Last summer when we went eclipse spotting, we met this guy.  He gave us a different sort of look.  As we ignored him, he then followed us, (always about 50 yards away), bleating his disapproval.  Apparently, we'd invaded his space.

### 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…