It also comes with great current times potential difference.
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Monthly Archives: September 2009
As Long as it's not Taylor-Theismann
Rhett analyzes a football collision. Momentum and Football
Sigh, Star. Sigh!
We said that it’s simple, and it is: it’s a brick wrapped in a piece of paper.
If you don’t have a couple of bricks (and we didn’t), they turn out to be cheap at hardware and home improvement stores. These are “cement bricks” — red dyed cement– and cost about $0.25 each. Wrapping them up keeps them from scratching up your shelves and books, but also from depositing cement debris everywhere.
The geek part is on the outside.
I Remember Her Cooking Show
The definition of a Julia set can get a bit complicated, but it can be thought of as an object that carves up four-dimensional space into two categories – belonging to the set, and not belonging to the set. How exactly the shape is carved depends on some very deep mathematics.
Dark Matter Left, Red Shift, Big Bang on Two, on Two. Ready? Break!
The Onion: NFL Scientists Postulate Theoretical Down Before First Down
Citing the extremely low level of entropy present before a normal set of football downs, scientists from the NFL’s quantum mechanics and cosmology laboratories spoke Monday of a theoretical proto-down before the first.
The Peasants are Revolting
“You can say that again” — The King of Id
My molar has apparently abdicated — it rejected its crown. Ugh. Fortunately I was able to have the dentist see me and fix my little problem.
No Butts About it: Truth is Stranger than Fiction
An assassination attempt, with emphasis on ass: the bomb was concealed in the orifice of choice for concealing items. I’d say convenient orifice, but it’s probably not all that convenient.
The bomb couldn’t be that big, and water (being a large fraction of the human body) isn’t very good shrapnel.
While the assassination proved unsuccessful, AQAP had been able to shift the operational paradigm in a manner that allowed them to achieve tactical surprise. The surprise was complete and the Saudis did not see the attack coming — the operation could have succeeded had it been better executed.
We know this wasn’t The Onion because there is no remark about how hindsight is 20-20, mention of a thorough probe of the incident, or talk of a push for new security measures. Or discussion of market penetration of security technology. (Oh, strike that last one. They say it here)
Via Schneier, who cautions us not to tell the TSA.
My Life is a TV Teen Drama
I don’t generally watch the teen-coming-of-age drama shows, unless forced (as I was on vacation; the episode of Degrassi was a cheap ripoff of Pump Up the Volume without the benefit of a topless shot of Samantha Mathis), but I’m sure this plot has been covered somewhere: Awkward Teen asks the Beautiful Cheerleader to the prom; she has recently split with Handsome Quarterback, but doesn’t immediately say yes to AT, so he assumes she will say no and asks Safety Date, who is much more likely to want to go with him, and she says yes. Immediately thereafter, BC also says yes. Depending on the context, either tremendous angst or hilarity ensues. Possibly both, depending on the quality of the writing.
How does this apply to me? A while back I got an invitation from an old navy buddy to give the keynote talk at the Southern Atlantic Coast Section of the American Association of Physics Teachers Conference. Keynote speakers are typically either famous, to some degree, within either the physics or pop-physics communities, or are attempting to become so by promoting a book, so I am not the Beautiful Cheerleader in this scenario. I figured this was an act of desperation, but I agreed, thinking it would be fun. Lo and behold, it turns out that the other speaker can make it. (Cut to commercial)
All is not lost. I’m getting my own slot during the conference, though that will be a tad awkward — the after-dinner talk (and the public talk that some conferences have) has more leeway in not being directly related to the theme of the conference. I don’t have any particular insight into teaching to share; certainly not an hour’s worth. Same goes for a lot of themes that show up here — I don’t want to make the mistake of trying to turn a 5-minute skit into a feature movie, because it rarely works (are you listening, Saturday Night Live?) So I’ll go with my plan and talk about clocks and timekeeping, with a few cartoons thrown in, and leave the connection to teaching as an exercise for the interested viewer. I was going to do a bit about how I’m at least a little bit famous, and promote the blog, and I may leave that in.
I was also toying with the idea of going with a minimalist presentation, with very few slides in the first part of the talk. The show-and-tell part, though, really needs the “show” as much as the “tell.” Still working on that. I lose the comfort of the “1 – 1.5 minutes per slide” guideline, and since talks will follow mine, there’s pressure to finish on time.
Not Pillows or Rugs
Throwies are simple LED circuits — the LED and a battery, with an optional magnet so they will stick to ferromagnetic materials.
Evil Mad Scientist Laboratories does a pretty exhaustive analysis on the circuits, looking at battery life and potential danger of these simple circuits. Some thoughts on throwies
This data shows a couple of interesting things. First is that the power-law model seems to hold fairly well. Second, the power function that pops out is not very different from that of the data from only the first half hour– integrating both out to 24 hours gives two answers– 150 mAh and 186 mAh –that differ by only 25%. The estimate based on the long data record (150 mAh) is the more accurate one, but this does suggest that we should be able to use the data from the first half hour alone to get a fairly good “factor of two” estimate of the performance over 24 hours.