Built on Facts

Archives for October, 2008

Sunday Function

Quick! Add up all the numbers between 1 and one trillion, inclusive! The story goes that the great Carl Friedrich Gauss in his days as a little kid in late-18th-century German primary school was told with the rest of his class to add up the numbers from one to one hundred. The teacher was probably…

Skimpy Saturday

This post is skimpy, that is. No scantily-clad women, though I bet it would drive up traffic! The post is skimpy because yesterday I spend several hours grading exams and six more driving to Louisiana. No time to write a good post and do the usual Saturday random observations and links. But usually everything on…

The Gravity of the Situation

I see that bailout is working wonderfully. Of course if it hadn’t passed and the stock market had behaved identically, we be hearing that we were fools not to pass the bailout. And they would be wrong. Yes, I know God Emperor Paulson hasn’t actually used any of his trillion dollar blank check yet. It…

#6 – Ernest Rutherford The New Zealand physicist Ernest Rutherford was an incubator of genius, and a genius himself. His position on this list is probably a little unorthodox as he wasn’t a very flashy scientist and he wasn’t a theoretical wizard. He just happened to be a surpassingly great physicist anyway. When Rutherford started…

Naming Momentum

Physicists like to name things after their discoverers. Sometimes if there’s a unit of measurement that doesn’t have someone’s name attached to it, they’ll grab the name of somebody who worked in that field and use it. Let’s take a look at some units, first a few examples not named after people: Length – meter…

Momentum

How’d the test go? Eh, ok I think. In particular I vapor-locked on a pretty easy question involving transforming E & B fields to another reference frame. There was another question where you had to prove that the energy-momentum tensor was Lorentz invariant, and I didn’t get that one either. The rest were pretty good…

Judgment Day

Today is Judgment Day number 1 of 3. “Why today, and why are there three of them?” you ask. Well ok, I exaggerated. It’s just the first of three exams in my electromagnetic theory class. Let’s see what’s on the test… “special relativity, Lorentz covariance of Maxwell’s equations, scalar and vector potentials, gauge invariance, relativistic…

Sunday Function

As we get closer to Halloween, let’s take a look at one of the few functions that might cause a stir in Salem. I give you the Witch of Agnesi, for several values of its free parameter a: The Witch is a geometric construction involving triangles that’s easier to show than describe: (Both images are…

The Streamline Future

This is of course from the 1939 World’s Fair. It represents the era of perhaps the most optimistic vision of science held by the public, from back when Progress was spelled with a P. The war put things on hold for a few years, and then we had a decade or so of glorious Streamline…

Define Energy

Thursdays I’m not a fan of, because I teach two classes back to back. Since both classes are associated with a lab, that’s six continuous hours in front of a chalkboard. Teaching I like, but six hours without a stopping leaves me pretty beat. That’s probably why in high school and below the teacher teaches…