December 7, 2009
Here's a very simple function:
You give it a positive real number, it gives you the square root. It maps 81 to 9, 100 to 10, 2 to 1.414..., and so on and so forth. It's pretty much the only one-argument function that's built into most pocket calculators, which says something about its utility…
December 5, 2009
Normally you wouldn't think of chick lit as experimental literature, but the interplay between the book and film versions of Bridget Jones's Diary is so bizarre as to be practically science fiction.
The novel is itself a very loose retelling of Jane Austen's classic Pride and Prejudice. That novel…
December 4, 2009
I'm a relatively light sleeper. The ear-piercing klaxons that are most alarm clock buzzers are way more than necessary to get me out of bed, and even most music stations are more than I want to deal with abruptly when I'm trying to work up the will to leave warm comfort to go to a day's work. So…
December 2, 2009
A few days ago we looked at what a Lagrangian actually is. The short of it is that it's the kinetic energy minus the potential energy of a given mass*. More importantly, if you construct the classical action by integrating the Lagrangian over the time (see the previous link for a more full…
November 30, 2009
Just a quick one today, as I get caught back up from Thanksgiving. We all know and love the very basic quadratic function. Any second-order polynomial will give you a nice little parabola, which of course is ubiquitous in physics. We all know what that looks like. But what if we're willing to…
November 27, 2009
Yesterday, as expected, severe underdog Texas A&M lost to #3 ranked Texas. Not as expected, the game was competitive right to the end, with an upset being threatened down to the final minutes. It was a great game to watch, with a final score of 45-35 - the highest total score in the history…
November 26, 2009
First of all, happy Thanksgiving everyone! I hope you spend the day happily with the people you care about, and remember to spend a moment or two reflecting on the things for which you're thankful this year. Now on with the show:
Back when I first started writing this blog, I focused mostly on…
November 25, 2009
A quick and simple way to roughly check the calibration of a spectrometer is to point it at the ceiling. Fluorescent lights put out a particular spectrum, and by comparing the colors the spectrometer senses to the colors you know the light emits, you can see if your spectrometer is accurate to a…
November 23, 2009
If you look at an incandescent light in a spectroscope, you'll see a broad and continuous range of light emitted over a large portion of the visible spectrum. This combination of colors looks white to us. At the other extreme, laser light generally consists of just a tiny slice of the frequency…
November 20, 2009
Around ScienceBlogs, people who don't accept global warming as a real phenomena tend to get called denialists. In the interests of full disclosure, I should admit that I'm not a denialist but rather a global warming defeatist. Doesn't matter how bad or not CO2 is, ain't nothin' gonna stop it.…
November 19, 2009
Ok, see counselor Troi firing her phaser?
You see this kind of thing all the time on film in scifi. Whether it's Star Trek, Star Wars, or pretty much anything else, energy beams fired from future weapons are visible. Usually someone will point out that in fact laser beams are not visible in this…
November 18, 2009
There's a little bit of buzz burbling around over Al Gore's scientific goof during a Conan O'Brien interview. Discussing geothermal energy, he said the following:
It definitely is, and it's a relatively new one. People think about geothermal energy -- when they think about it at all -- in terms of…
November 15, 2009
We're doing two functions today. If I'm not mistaken we've done each of them separately, but there's a famous and interesting relationship between the two that's always interesting to look at. Like very many interesting mathematical facts, it has to do with the prime numbers.
As such the first…
November 13, 2009
Whew! Interesting day around here yesterday, no? There's more controversial topics out there: abortion, health care, gay marriage, Iraq, and a few others. But not many. It's good for sparking discussion, but I also know that some large (probably majority!) fraction of you would prefer to hear…
November 11, 2009
God help me, I resisted mightily. If my fellow SB friend Greg wants to spin the Ft. Hoot shooting as a cause for gun control then frankly there's pretty much nothing further to say. You'd think a @#$% major in the @#$% army on a @#$% army base just might not have been terribly inconvenienced in…
November 11, 2009
On Veterans Day we commemorate the living veterans of the American armed forces. On Memorial day we commemorate those who lost their lives. We should also spend a moment to remember those who helped make sure more soldiers fit into the first category. Though I've made the point before on this…
November 9, 2009
Again I have to apologize for the sparseness of posting lately, but I've got two research projects going full blast and time has not been something I have a lot of. I'll still be writing at least a few times a week, and you can't beat the price. ;) In any case once things cool down just a little…
November 7, 2009
Of late president Obama has taken a little bit of heat for his frequent (and mostly male) golf outings. Before him, president Bush took the same sort of heat for his golf and vacations. If you were willing to dig a bit through the news archives, I'd bet you could find similar tut-tutting about…
November 6, 2009
Here's a question which pretty much everyone gets wrong. But the readers of this blog aren't just a random sample, so I bet most of you will get it right:
Two identical vehicles A and B, both traveling at speed V directly toward the other vehicle, collide exactly head-on. At another test track,…
November 4, 2009
For most of human history, our ability to perceive and understand very fast optical events has been limited by the temporal resolution of the human eye. Things that happened too fast were a blur, and all we had to go on was guesswork. Take, for instance, this 1821 painting of a horse race:
If it…
November 2, 2009
These days pretty much everyone knows that mass and energy are two sides of the same coin, as discovered by Einstein. In fact this is so well known that the average man on the street - knowing nothing at all of physics - would still recognize the expression even if he didn't know what it meant or…
October 30, 2009
There's an interesting article in New Scientist that purports to describe "seven questions that keep physicists up at night". The list is very heavy on the "deep questions" that tend to percolate around the more esoteric quarters of the high-energy physics world, and not so much on the vast bulk…
October 28, 2009
Grab a book, or an empty DVD case, or anything else that's a uniform rectangular solid. If it's a book, you might want to secure the book closed with tape or a very lightweight clip, because we'll be throwing it in the air. We want to test a theory.
In classical mechanics we know that each solid…
October 26, 2009
There's a stereotype that it's declasse for us intellectual aesthetes to enjoy football, but I don't care. I enjoy it anyway. Whether you spent any time this weekend watching football or not, I'd like to pose a quick and (maybe!) easy vaguely football-related problem to exercise your brain to…
October 23, 2009
The deserts of New Mexico can get blazingly hot and bone-chillingly cold, extremes of temperature familiar to the outdoorsman in that kind of terrain. A few hundred feet below the ground in Carlsbad Caverns, the temperature is essentially stable in the mid-50s no matter how scorching or frigid the…
October 19, 2009
There's a question that gets posed toward the beginning of intro physics classes to gauge the students' understanding of acceleration. If you fire a bullet horizontally while at the same instant dropping a bullet from the same height, which hits the ground first?
The point is to think clearly…
October 18, 2009
Edit: The previous version of this post required some fixing, as I boneheadedly mixed up the O and Ω notations. The rest of it should still be good.
When you invest in stocks, bonds, mutual funds, or just about any other major investment vehicle, you'll hear a standard but important disclaimer. "…
October 16, 2009
Today Texas A&M was a bit of a madhouse. Huge crowds, hundreds of police, unseasonably-suited and grim-faced men with mirrored sunglasses, unmarked helicopters circling overhead, TV cameras circling below, and completely borked traffic.
Why? Not just one but two Presidents of the United…
October 15, 2009
I propose a Fermi Problem.
Over the lifetime of an average light bulb, what is the total mass of all the electrons that have flowed through?
Work on that if you have an idea how to proceed, or just take your best plausible guess. Remember it's a Fermi problem, so we're looking for estimates…
October 14, 2009
Supposedly there's no such thing as bad publicity, and indeed just about every large organization from business to charity spends tremendous amount of time and money trying to get noticed by the public. You'd think therefore that it would be a good thing that particle physics gets the press it…
