Tertiary Source

Ice tray stalagmite

2010-02-21 20:19:22
Look! I had a stalagmite in my ice cube tray.
an ice cube tray
what is that?
it sticks out against a card

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

[none]

Older questions

Today's Stardate gave the "exact time" of the full moon. This is presumably when the moon is at opposition. But "full moon" historically described when the moon was at its brightest in the sky. Does the moon's libration ever make the moon observably brighter at some time other than at opposition?
2009-06-07 Sunday 10:27:20
The representation of an integer in base b has some digits dn,⋯,d0. For example the number 42 = 4×101 + 2×100 has d1=4, d0=2 in base b=10. It's sometimes convenient to switch to a different base, frequently binary (b=2) or hexadecimal (b=16). Is there ever a reason to switch to noninteger b? What pathologies would such a representation have?
2009-04-20 Monday 14:39:54
Yesterday's solstice was the day when the northern hemisphere gets less solar irradiance than any other. In most countries this is "midwinter," but in the United States it's "the first day of winter." When did this label change?
2008-12-22 Monday 06:58:50
A jugful of water adds some thermal inertia and makes an empty refrigerator cool more efficiently. A tubful of water ought to do the same thing for drafty old house. How big is the effect?
2008-12-08 Monday 09:59:41
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
If you pull two connected blobs of Silly Putty apart slowly, the thread between then stretches plastically; if you pull them apart quickly, it fractures cleanly. What sets the threshold? How sharp is it?
2008-10-20 Monday 16:16:27
How strong is the correlation between income tax witholding / refunding and tolerance for government spending?
2008-10-14 Tuesday 23:05:05
Among the different Nobel prizes, there is a big spread between when work is done and when it is rewarded. The physics prizes seem to go to people whose work decades ago has shaped research since, while the peace prizes seem to go to people who are actively doing notable things right now. What's the distribution of times between doing something noteworthy and winning a prize for it? What about less famous prizes?
2008-10-08 Wednesday 10:54:38
Fresh Air interviewed Katharine Jefferts Schori, the primate of the US Episcopal Church, who has a doctorate in oceanography. Are advanced degrees in the sciences more common, or less common, in the clergy than in other nontechnical fields? How does the frequency change across different denominations?
2008-10-08 Wednesday 10:27:03
What other neat tricks could you pull off using volunteer hardware as a distributed sensor network?
2008-09-30 Tuesday 18:39:26