March 27, 2009
Apologies for the light posting. Busy week, and it's going to be a busy weekend too in physics land. Well, that's what I signed up for.
This caught my eye though. Via Swans on Tea though, I see a great demonstration of physics as art. There's a story of Feynman and several other physics…
March 25, 2009
Kal-El, native of the planet Krypton, came to Earth and was adopted by Jonathan and Martha Kent. Being a Kryptonian, he found that he had superhuman powers and used them for good as Superman[1].
We all know the story. But what do we know about Krypton? Any information would be a dramatic coup…
March 24, 2009
Cormac McCarthy is with good reason widely considered to be among the finest living American writers. The literary scene has appreciated his work for some time; the general public (including myself, though I do a lot of reading) was first exposed to his work in the uncommonly faithful film…
March 23, 2009
Missiles are a problem if you're fighting a modern war. You can get out of the way or you can hide behind something, but that's about it. Now anti-missile technology has had some success dealing with mid-range missiles. The Patriot system whose success was limited during the Gulf War has since…
March 19, 2009
Thursday and Friday of this week are the staff and faculty equivalent of spring break here at Texas A&M. I'm going to be spending them on the road, visiting family and friends. As such Built on Facts is going to be on break for a few days. We'll be back Monday - possibly sooner.
Until then,…
March 18, 2009
It's not all that often I agree with Mike Dunford politically, but in writing about the AIG bonuses he's right. The bonuses ought to stay with the executives who were paid them. Neither congress nor the president ought to try to tax these bonuses back.
Now obviously no executive at a failing bank…
March 18, 2009
Here is a question. It's a sort of subtle question, but one that can be answered with freshman-level physics. But it's an excellent test of understanding. I'm not promising that the question itself is not in some sense a "trick" question, but the trick is in how you might think about the physics…
March 17, 2009
Sometimes I watch Survivorman on the Discovery Channel. It's a good show - much better than that other one - by virtue of the fact that the survival is real and he doesn't have a camera crew around to help him out. Sure he has a way to contact rescue should something go wrong, but it doesn't…
March 16, 2009
Driving in my car for five hours today, I had plenty of time to think about velocity. There's not much you can do about it, speeding doesn't take much time off the trip but it does add the risk of an expensive ticket. We single classical particles don't have a lot of options for getting from place…
March 15, 2009
Well, it's Gabriel, Gabriel playin'!
Gabriel, Gabriel sayin'
"Will you be ready to go
When I blow my horn?"
- Cole Porter, Anything Goes
The commenters in last week's Sunday Function proposed an excellent idea for this week. As we did then, we'll start simple and work up to it. Graph the curve f(…
March 14, 2009
Whew! Busy week for me, hence the missing post or two. Traditionally Saturdays on this blog tend to be non-physics fare - either links, commentary on something nonscientific, or whatever. Today I think it will be the celebration of Pi Day!
Pi Day: As you know from the SB main page, today is pi…
March 12, 2009
A reader writes in with a question about the physics of Star Trek:
When the Enterprise goes into warp speed (which as I take it are multiples of the speed of light, warp 5, 5x the speed of light, etc.) and they show the ship zooming through the cosmos, they always show the stars its passing as…
March 11, 2009
Conservative forces, that is!
Hold a basketball in your hand and move it around. When you move it up, you do work against gravity. You have to put energy into the system to get it to gain height. Relax your arm, and the force of gravity pulls it downward, converting that potential energy into…
March 9, 2009
Imagine the scientists of the world got together and decided they didn't like the meter as a unit of distance. They were tired of traveling such long distances to conferences and decided that by redefining the new meters as two old meters, suddenly the plane flight was only 1000 kilometers instead…
March 8, 2009
Let's start with a pretty simple function. It's not this week's official Sunday Function, but we'll use it to get there.
Take the number 1, divide it by x. Pretty easy. Now imagine putting a dot at the point x = 1 on the x axis, and draw a line straight up from there to the curve formed by…
March 7, 2009
As ScienceBlogs' resident firearms enthusiast (I might own more guns than the rest of the SB writers combined - and I don't own very many), I've occasionally written about gun rights and related issues. One of the things I've noticed is that a lot of people aren't very familiar with what gun laws…
March 6, 2009
Via xkcd, an unusually clever comic even by the standards of this unusually clever comic:
It goes right to the heart of one of the greatest philosophical difficulties of science. All we can do is measure correlation. We can never be assured that we're not just getting lucky and that in fact the…
March 5, 2009
ScienceBlogs' own Chad Orzel has on a number of occasions discussed the photon concept in relation to physics pedagogy. He thinks (as I do) that it's a good concept to teach early even though formally speaking photons are considerably more complicated than the "particle of light" idea that's often…
March 4, 2009
Spider-Man, of mass 90kg, is perching 10 meters above the ground when he notices his (depending on the continuity) crush/girlfriend/wife Mary Jane (50 kg) being menaced by... I dunno, a menace. I'm more of a DC fan really.
He swings down toward her to spirit her our of harm's way. Assuming he…
March 3, 2009
It occurs to me that I still haven't scored and posted the winners of the BoF 2008 Election Prediction Contest. Formally I still can't, because the Minnesota senate race has not legally been resolved. For all practical purposes it has, but I like to be sure about things before I go and award the…
March 2, 2009
In high school and introductory college chemistry you're going to do a lot of problems involving the ideal gas law. It runs something like this:
PV = nRT
So simple I don't even have to typeset it. Pressure times volume equals the number of moles (n) times a particular ideal gas constant (R) times…
March 1, 2009
A tricky one:
At x = 2, f(x) = 1 + 2 + 4 + 8 + ...
Which, uh, is clearly not going to end anywhere finite. The series fails the single most basic necessary (but not sufficient) condition for convergence of infinite sums - that the terms of the series approach zero as you go farther and farther up…
February 27, 2009
Here's a rather harrowing video I recently watched. It's a commercial airliner on approach to a runway during a severe crosswind. The plane is attempting to perform a maneuver to keep itself flying over the runway without drifting off course, but this requires flying at an angle into the wind.…
February 26, 2009
Swans on Tea posts a parody Pesudoscientific Method followed by cranks worldwide. One item:
Accuse anyone asking for empirical evidence of being 'close minded'; try to protect your ideas from this sort of pessimism.
I hate to be pessimistic, but I can't help what I notice. I've listened to…
February 25, 2009
Like the Indiana Pi Bill before it, the Illinois Legislature's attempt to weigh in on the planetary status of Pluto is kind of silly. But not so silly as you might think.
The Indiana Pi Bill in popular legend was an attempt to bring the stubborn decimal expansion of pi into accord with the…
February 24, 2009
Whew. You may have noticed things have been quiet around here. There's a reason. This weekend I drove to Slidell, Louisiana to be the best man at my friend Aaron's wedding. He was my college roommate at LSU, and he's about the best friend a person could ask for. After graduation, he's gone on…
February 19, 2009
If it's zero degrees outside and it becomes twice as cold it was before, what is the temperature?
Usually it's presented as a joke. I'd like to consider some alternative interpretations.
1) It could literally mean the number denoting temperature divided by two. This has a number of unfortunate…
February 18, 2009
Excellent job on yesterday's physics problem. Several people got the right answer, and in lieu of answering it again myself I'm going to let commenter arne fill us in:
Well, electrostatics follow the principle of superposition. We can see that the problem is symmetrical under the choice of loaded…
February 17, 2009
Mind if I give the readers who've taken an electrostatics class something to noodle over?
Consider a cubic box consisting of six sides of which five are held at a uniform potential of 0 volts. The top side is held at a uniform 100 volts. What is the potential at the center of the cube?
Here's a…
February 16, 2009
Despite the title, this isn't about those the politics of science, or even the science of politics. It's about talking in public.
Watching President Obama's first press conference, I was struck as I usually am by the sheer uselessness of it all. The press either asks bilious trivialities (…
