Tertiary Source

Eleventy-one thousand eleventy-one

2009-08-14 09:08:00
Here's a million-to-one photo I took yesterday:
odo: 111111, 44 mph

Remember the significance of the three circles!

2009-07-10 14:57:28
When I was a freshman I took Philosophy 110. It was a big lecture, and the professor had a habit of rambling (which I mostly found entertaining); there was the customary falloff in attendance as the term went on. During one lecture the professor was working up to making three points and put some bullets on the whiteboard:
o
o
o
He then promptly distracted himself with a tangent about how boring people drive Fords, and whenever you see a Ford it's being driven by a boring person. After a couple minutes of this he turned back to the board and said, "I have no idea why I made these three circles. They must mean that boring people drive Fords." This got a chuckle out of the class, and he added, "Remember that! It'll be on the final."

Vaccine fears and risk tradeoffs

2008-12-26 11:28:25
This weekend's This American Life included interviews with some of the participants in this summer's measles outbreak. I learned about the outbreak from a somewhat overblown reaction from Phil Plait. From memories of Plait's older material, I expected a little lesson in conditional probability. Not finding one, I did an analysis of my own. I reached the surprising-to-me conclusion that, even with this summer's outbreak, the risk tradeoff between measles exposure and vaccine side effects is not totally unbalanced. My writeup at the time got lost in comment noise, so I'll condense it again here.

A duck from the Economist

2008-12-08 10:32:10

Here's a nice duck from the Economist. It's interesting that coups d'etat have become less common in recent years. It's also interesting that these commandos are reaching through the grid lines to pat the data.

Coups and attempted coups worldwide

Rail fuel economy

2008-12-05 01:04:24

Dylan Foley pointed out to me that my question about CSX's advertised fuel efficiency has previously gotten attention from FactCheck.org.

Musical Doppler self-sonar

2008-11-14 18:42:18

If you stand reasonably close to a road, the sounds of passing traffic get Doppler shifted: they start off high and end up low, "wheeeee-oooooom." Professional and amateur musicians have sophisticated training in recognizing frequency ratios. (Though, explicitly mentioning the relationship between frequency/wavelength ratios and intervals is more common when players of string instruments experiment with making harmonics.) How accurately could you estimate the speed of a passing vehicle by the sound it makes?

What's the antimatter content of a banana?

2008-10-21 11:06:37

Antimatter is strange, exotic stuff, right? Only produced in dangerous physics experiments? Leads to complete annihilation with ordinary matter?

Sort of. It's a question of quantity.

Recent questions

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Older questions

In a letter to Physics Today Roger Musson writes that the terms "Stone Age," "Iron Age," etc. refer to the material used most commonly to construct knives. This means we are currently in the Stainless Steel Age, possibly changing to the Plastic Age. By some reasonable measure, when would the transition happen?
2009-05-28 Thursday 17:37:37
Computers have fast storage with limited space (RAM) and slower storage with fewer overall limits. How could this set of constraints change and make computing fundamentally different? How would similes about how "your brain is like a computer" change? Is there a better model for the brain?
2009-02-23 Monday 15:23:33
My fan-driven humidifier makes my house feel colder. How much heat does it pull to vaporize the water it does?
2008-11-14 Friday 16:59:35
Gerrymandered Congressional districts tend to protect extremists at the expense of moderates. Will the House be more or less polarized after the turnover in yesterday's elections?
2008-11-05 Wednesday 12:39:29
Suppose I wanted to check the accuracy of an ensemble of weather forecasts (e.g. "30% chance of rain tonight"). What's the right metric for doing this?
2008-10-09 Thursday 10:35:34
Suppose two stationary states in a nucleus differ only by their (total) isospin. What's physically different between them?
2008-10-07 Tuesday 09:53:07
The Economist claimed that an oil price spike on September 22 (or thereabouts) was a quirk of timing, due to some minor supply quirk that happened to happen in the last couple days to fill contracts for delivery October 1. When I hear about "the oil price" on the news, what am I hearing? Is there information in the spread between short- and long-term prices that isn't reflected in either market alone?
2008-10-03 Friday 00:57:19
If you feed a Markov chain its own output, does its behavior get more stable or less stable?
2008-09-29 Monday 17:33:56
When using χ2 minimization to estimate parameters from some data set, what fraction of the fits stop converging in the "wrong" place?
2008-09-28 Sunday 16:55:01
You can't interact with a physical system without disturbing it, though you can ignore the disturbance in the limit where ħ is small. Similarly, you can't interact with a market for some product (by asking or buying or offering or selling) without affecting the "market price" seen by others, but you can neglect that change unless your exchanges comprise a large fraction of the market. There is some correspondence here. Clearly it'd be easy to take this correspondence as justification for saying some really dumb things. Are there any useful insights there?
2008-09-26 Friday 14:50:23