How do you learn about things?
-
Experience: things you do, or things
that happen to you.
Your observations.
-
Primary sources: you heard about it from
someone who experienced it. "We performed the following
experiment." Scientific articles; investigative journalism;
diaries; transcribed interviews.
Someone else's observations.
-
Secondary sources: you hear summaries or
distillations of primary sources, without reference to the
authors' own experience. "An article in this week's Journal of
Scientific Spiffiness reports …." Science journalism;
unbiased but non-investigative reporting.
Someone's reports of someone else's
observations.
-
Tertiary sources: you hear distillations
of secondary sources, without direct reference to any primary
sources. "The Associated Press reports that scientists
have …."
Based, in principle, on someone else's
observations.
Of course these categories are pretty fuzzy. So, some fuzzy
questions:
-
How much of what you know, and care about knowing, comes from each
category?
-
How much weight do you attach to new information from each
category?
-
How good are you at telling one source of information from
another?
My goal here is to publish questions every day, and essays once a
week.
So far (March 2009, about six months after starting)
it's been more like a question a week and an essay a month.
Recent questions
[none]
Older questions
The Greenland and Antarctic landmasses are under a mile of ice.
Supposedly if this weight were removed the landmasses
would "rebound" out of the mantle. How high would they go?
2009-02-27 Friday 23:30:51
To an outside observer,
an object dropped onto a black hole never actually
crosses the horizon; it approaches the horizon
asymptotically and light from it becomes more and more redshifted.
Suppose I drop a room-temperature blackbody in a hole.
How long does it take before the redshifted temperature
is colder than the Hawking temperature of the horizon?
2009-02-27 Friday 23:24:26
A metric for cheap eating: calories per dollar?
2009-01-27 Tuesday 11:48:35
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
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
Suppose I replace an incandescent light bulb with a more expensive,
more energy-efficient, longer-lived light — a CFL, an LED,
whatever — based on the expectation that it'll cost less over
its life. How old does my incandescent bulb have to be before I
actually save anything?
2008-10-28 Tuesday 21:42:08
If Hawking's connection between black holes and thermodynamics
is right, astrophysical black holes --- for which general
relativity predicts everything bizarre happens well inside the
horizon, and for which there are observational evidence --- are at
the zero-temperature limit. What's the "warmest"
black hole for which there is observational evidence? What's
the transition "temperature" where quantum gravity starts
to matter?
2008-10-06 Monday 19:45:48
An
observation
by Consumer Reports, that breakfast cereals marketed to
children aren't terribly nutritious, has gotten some
evening-news press. The main contribution of the Consumer Reports
release seems to be that they bought a bunch of cereal and read the
nutrition labels. What's new here? Has the composition of
existing products been tweaked? Have some sweeter brands been
introduced to replace healthier ones? How do these sorts of news
blobs correlate with sales, or with marketing spending?
2008-10-06 Monday 12:29:26