Built on Facts

Archives for September, 2008

Sunday Function

Take as our starting point this function, defined on the positive whole numbers: All it does is add together the fractions above, stopping when you hit the fraction specified by your particular choice of n. As you increase n and thus add more fractions to the sum, you’ll end up with a plot of the…

Bacon and Asimov

Friday I met my first ScienceBlogger in person. Nick Anthis from The Scientific Activist was in town, and as he’s a former Aggie we got to trade a few stories about the university and the different kinds of work we’re doing. He’s a cool dude! It was very nice meeting him, and I think it…

How to be a good TA

I’ve taught seven recitation sections as a graduate student, and this semester I’m teaching three more. Between them it’s several hundred hours of standing in front of a classroom teaching. That’s nothing compared to career teachers and professors, but it’s a decent bit of experience as far as TA teaching goes. I put a fairly…

Charging the Earth

Teaching Physics 201 has me digging out some of my old favorite concept-y problems. Nothing dramatic in the mathematics, but at the 201 level you can’t even assume knowledge of derivatives. But you can try to catch their minds with interesting examples. Here’s a classic one: You’ve got the earth and the moon. They have…

Two Happenings in Physics

Physics is a continuous thing, progressing steadily forward with only rare dramatic leaps. This is not the kind of style that makes for flashy news stories in the popular press. When there are interesting things being reported, they’re usually wrong. “Faster than light” laser pulses, quantum teleportation, invisibility cloaks… if it’s in the popular press…

Walking the Plank

In honor of Physics 201 which I’m teaching this semester, I present a very elementary statics problem. Here we have a board of uniform composition and weight W. It has length l and the supports are separated by a distance s. What are the two forces (call them A and B) on the boards? The…

The Ladder

Fundamentally, you can start off with the Standard Model. It’s not perfect, but it’s a pretty good description of the particles and forces of nature especially at the mostly low energies of our soar system. Using quantum mechanics you can built up those particles into distinct nuclei, and calculate how they can fuse to form…