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

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Older questions

How does the Stephan-Boltzmann constant σ "run" at temperatures where radiation modes other than photons become accessible?
2009-01-31 Saturday 13:34:02
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
In quantum mechanics, the one-dimensional square well with periodic boundary conditions has a solution with wavenumber zero. How does this compare to the Goldstone boson in a very stiff "Mexican hat" potential?
2008-11-03 Monday 23:06:09
Supposedly volcanism on Io is caused (or enhanced) by tidal heating from Jupiter. What power does tidal heating dissipate in the Earth-Moon system?
2008-10-23 Thursday 13:03:59
What makes glassy smooth patches on the surface of a larger body of water? Why are the patches partially stable against rippling from outside?
2008-10-23 Thursday 06:05:41
Under what circumstances are disease screenings "preventative medicine"?
2008-10-21 Tuesday 17:14:47
A paper in PLoS Medicine argues that an artificial scarcity of high-profile journals may distort what appears in the scientific literature, in favor of spectacular, surprising, and possibly wrong results. The analysis seems to favor medical and biological publications. Do the conclusions apply to physics publishing?
2008-10-21 Tuesday 14:31:48
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
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
What's the pressure inside an unopened soda bottle (or can)? What's the rate at which CO2 comes out of solution at ambient pressure? How much does the bubbling change the temperature of the liquid?
2008-09-23 Tuesday 19:19:09