Built on Facts

Archives for February, 2010

Has the speed of light changed?

A reader writes in with a question about the speed of light. Since the meter and second are defined in terms of that speed, how would we be able to tell if the speed of light is changing or has changed throughout history? It’s a good question. According to the official standard, a meter is…

Sunday Function

Here’s a simple function that’s not so often found in mathematical physics, but it’s still a nice showpiece for exhibiting some interesting behavior: I’ve only plotted it for positive real x, because for x less than zero it starts spitting out complex numbers in a very unfriendly way. We’re only considering it along the domain…

The Physics of Curling

Unfortunately it’s rarely on TV more than once every four years, but I have to say I’ve really gotten to curling. Not only is it interesting to watch, it looks like it’s actually a sport that could be played for fun at the beginning level. Unfortunately there doesn’t seem to be a whole lot of…

Grad school and a major (good) event in my personal life have been gobbling huge swaths of time, hence the comparative silence around here. I’m afraid we may be down to a few times a week for the next few months. I hope y’all’ll bear with me. (“Y’all’ll” is of course the standard contraction for…

Sunday Function

Pretty much every high school student can quote the formula for the area of a circle: it’s A = pi r^2, where r is the radius. Most of them can do the same thing for the volume of a sphere: V = 4/3 pi r^3. You could, if you wanted, generalize the concept and call…

Watts up, doc?

Recently I bought a plug-in power meter, along these lines: It’s a nice little invention to have. You can measure both instantaneous power consumption as well as total energy used. Given that and your power bill, you can see how much it costs to run a particular appliance in real time. The answer is usually…

Failing at Gravity

A while back I mentioned I was starting the project of reading Neal Stephenson’s rather lengthy Baroque Cycle. I’m most of the way done with the second book, so we’re coming round to the 2000-page mark. It’s a brilliant work thus far, though it’s very difficult to summarize. The plot is rather, well, baroque. If…

Powering Spirit on Mars

I’m still not happy about NASA scrapping Ares and the manned lunar/Martian plans, but I’m less unhappy than I was. As long as unmanned planetary science picks up most of the slack I’ll grudgingly deal with it. The extra earth science is still stupid; if you want more of that, get NSF or NOAA to…

Super Bowl Coin Toss, Mathematically

Every year there’s a Super Bowl, and every year the whole shebang gets started by a famous person tossing a coin into the air. The team winning the toss gets to decide whether they want to begin the game on offense or defense. Theoretically this choice might produce an advantage. If so, would be interesting…

Sunday Function

Step right up, Ladies and Gentlemen! Get your ticket to see the True Oddities of the Natural World! Do not be taken in by the Shameful Forgeries at Inferior Circuses, here you will see Genuine Curiosities from the Mists of Time! Beside these Archaic Functions, the Two-Headed Horse or Whatever is a Mere Bagatelle! So,…