"When you get down &mdash and you will &mdash about the
state of society or the level of intellectual attainment in the
modern helter-skelter culture of so much of America, take heart
from the fact that there are still more public libraries in this
country than there are McDonald's."
— David McCullough,
Commencement 2001, University of Delaware
Is this on track to change? When?
2009-06-05 Friday 07:52:43
I can make a partially deflated helium balloon neutrally buoyant by
trimming bits off its string. How big are the variations in the
"right" counterweight in an ordinary room?
2009-04-22 Wednesday 12:52:43
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
There's a theorem in control theory that sets limits on how quickly
the gain of a feedback system can change with frequency without
driving oscillations. This is the logic behind using the
integral and/or the derivative
of the feedback signal in
mechanized control systems. One factor in the current financial
tension between short-term and long-term risk
a problem that
also appears in smaller-scale "markets."
Suppose this tension were reduced by, say, paying fund managers
investments less liquid than cash, in some quantifiable way.
Are cash commissions guaranteed to have boom and bust oscillations?
Do oscillation-free commission schemes exist?
2008-12-31 Wednesday 10:03:07
New "open" signs at restaurants, with bright red and blue LEDs,
bring out some chromatic aberration in my glasses: viewed
peripherally, the different-colored parts don't line up.
Quantify? Why have I only just started to notice this?
2008-11-11 Tuesday 09:44:38
Passing traffic makes Doppler-shifted noises ("wheeee-oooom").
Useful trick: map between musical interval of the shift
and the speed of the traffic?
2008-11-11 Tuesday 09:38:19
Supposedly volcanism on Io is caused (or enhanced) by tidal heating
from Jupiter. What power does tidal heating dissipate in the
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
2008-10-23 Thursday 06:05:41
The Economist claims that some 1200 people have died crossing from
Mexico to the US since 1990, compared to about 300 killed trying to
cross the Berlin Wall during the 28 years it was up. Fatalities per
mile? Fatalities per legal crossing? Estimates of successful
2008-10-11 Saturday 09:54:20
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