Skip to main content

Dance Parties and Books

Lala Land dance Parties have become a thing of late at our house.  The kids put on the soundtrack, and vamp around the room dancing every which way  Four year-old No. 2 has settled into a decidedly beatnik shimmy of late.  He’ll plant his spread feet, shake his shoulders, and then, as he pulls his feet together, ooze to some other spot in the room before doing it all over again, perhaps throwing in a spin with his shimmy this time.  I’m convinced he’s channeling the dance he watched Audrey Hepburn at the French cafe in Funny Face.

Six year-old No. 1's, dances tend to be influenced by whatever she’s reading.  When she’s heavy into comic books, she might dance like a robot, making start again, stop again, syncopated movements around the den ala Cliff Steele, Robotman of Doom Patrol, or she might move from tree pose to tree pose spinning as she goes, ala Poison Ivy of Superhero High.  This week, No. 1 discovered a beginning ballet book from the ‘50s at the university library, so she’s moving in a slow and composed manner from one ballet pose to another.

Two year-old No. 3, has recently discovered the joy of spinning.  She’ll twirl through the room, pausing briefly to see if the room will in turn twirl on its own before launching into her next spin.  Today though, she’s latched onto what No. 1’s doing, and is earnestly imitating her every move.

I’m the unintended beneficiary of this particular dance party.  It just happened to erupt as I was sitting on the couch reading Ben Hewitt’s “Home Grown.”  Minding my own business, reading my book, I notice that No. 3 is doing something new this time.  After each ballet pose, she’s taking a full second to peer intently, directly at me with a focused gaze.  Perhaps she’s wondering what I think of her dance moves?  That’d be odd since none of the kids have ever so much as glanced at any of their unintentional audiences before.  They embody the phrase ‘dance like no one is watching.’  Just in case, the next time No. 3, peers my way, I grin and give her a thumbs up.  Her gaze is unflinching.  The grin, the thumb’s up, it’s like they never happened.  No. 3 is completely focused on... what?  I try a few more grins on the next couple of gazes between poses, but still nothing.

Finally, as the song ends, No. 3 strikes out directly across the living room, straight for me.  Well, not me actually.  Reaching out, No. 3 takes ahold of my hands and the book they hold, pulling it down and towards her.  Studying the image for a moment , her gaze changes from intent to resolved.  Sure enough, that is a book with kids in a forest on the cover, just like herself and her sibs.  Content, No. 3 returns to dancing on the next song, once again completely oblivious to the room’s other non-dancing denizens.


Popular posts from this blog

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…

Lost Phone

We were incredibly lucky to have both been in university settings when our kids were born.  When No. 1 arrived, we were both still grad students.  Not long after No. 2 arrived, (about 10 days to be exact), mom-person defended her dissertation and gained the appellation prependage Dr. 

While there are lots of perks attendant to grad school, not the least of them phenomenal health insurance, that’s not the one that’s come to mind for me just now.  The one I’m most grateful for at the moment with respect to our kids was the opportunities for sheer independence.  Most days, we’d meet for lunch on the quad of whatever university we were hanging out at at the time, (physics research requires a bit of travel), to eat lunch.  During those lunches, the kids could crawl, toddle, or jog off into the distance.  There were no roads, and therefore no cars.  And, I realize now with a certain wistful bliss I had no knowledge of at the time, there were also very few people at hand that new what a baby…

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…