Built on Facts

Archives for February, 2009

De Plane!

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. It’s difficult and the pilot…

Uncertainty

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 economists on everything from NPR to…

A Matter of Definition

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 Biblical…

Back in Action

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 to…

Half as cold

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 features. For one, it depends on…

Potential II: Electric Boogaloo

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 side. We know that if we…

Finagling the Laplace equation

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?…

Scientists vs. Politicians

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 (baseball steroids, the usefulness of “bipartisanship”, etc)…

Sunday Function

On the surface it’s one of the most boring possible functions. Two straight horizontal lines: the Heaviside step function. Usually denoted θ(x), it’s equal to 0 if x is less than zero, and it’s equal to one if x is greater than zero. At x = 0 exactly it doesn’t really matter what it is…

Physics. Also maybe computer games!

News from around the world of physics: Near and dear to my heart is any clever experiment involving lasers. And via Swans on Tea, this one’s a doozy. It’s paddleball, but instead of a rubber ball you have a single atom. And instead of a paddle you have a beam of laser pulses. No string,…