Physics
drorzel | November 13, 2007 Jennifer Ouellette meantions it as the jumping-off point for her particle-wave duality post, but I want to spend a little time talking about this paper on single-electron interference (Science 318, 949 (2007)), because it's a very nice piece of work. There's also a Physics World news article about the experiment, which is pretty good, but slightly understates the coolness of the experiment.
The experiment here is extremely simple: They take a jet of molecular hydrogen, and hit it with extremely high-energy photons from the Advanced Light Source at Lawrence Berkeley National Lab. These…
drorzel | November 13, 2007The indefatigable Bora Zivkovic is soliciting contributions for the science blogging anthology The Open Laboratory. He's titled the post "Last Call for Submissions," but the actual deadline is December 20th. On or about December 19th, I expect a post title along the lines of "Wolf! Wooooolllllfffff!!! Oh My God, a Wolf!" but that's neither here nor there.
Being a commmitted advocate of Open Science, Bora has posted the full list of submissions to date. Looking it over, my main reaction is "Where's the Physics?" It's not just that this blog isn't nominated, but a general lack of physics posts…
drorzel | November 9, 2007 I have a bunch of science news sources in my RSS feeds, and every evening, I scan through the accumulated articles to try to figure out what physics-related stories there are to talk about. Sometimes, it's hard to find anything, but other days, you get stories that lead to four press releases at EurekAlert (one, two, three, four), a write-up at Backreaction, a Physics World news story, and a Dennis Overbye piece in the New York Times. I guess I really ought to say something about the new results from the Pierre Auger Observatory, published this week in Science (Science 318, 938 (2007), if…
pontiff | November 8, 2007Many of you know I'm a big fan of funny/creative paper titles. What with journal editors squashing every last ounce of humanity our of scientific papers, it always makes me happy to see someone else fighting the editorial machine. Today a friend sends me "Heavy Ion Collisions at the LHC - Last Call for Predictions," by S. Abreu et al arXiv:0711.0974 (scirate here.) which cracks me up.
I'm not sure why it cracks me up, but probably because it makes me think of an overloaded boat leaving the dock with a bunch of crazy haired theoretical physicists flinging themselves at the boat at the last…
drorzel | November 8, 2007There are a lot of high-tech tools that are absolutely essential to the functioning of my lab. The diode lasers I use are a couple hundred bucks each, and only available from a handful of companies. I've got a couple of digital oscilloscopes that are really impressive instruments, packing a huge amount of signal-processing power into a single smallish box. I have an infrared viewer that I use to see the beam, and the lab is literally just about shut down when a colleague needs to borrow it.
Something that people outside of experimental physics don't really appreciate, though, is that there…
pontiff | November 5, 2007(With apologies to Jorge Luis Borges.)
The universe, which others call the cellular automata, is composed of an indefinite (and perhaps infinite) number of square rooms, each room having four doors (in what we can, for lack of a better choice, assumelie in the cardinal directions of north, south, east, and west.) Each door leads to an adjoining room which is identical to the other rooms except for one salient feature. In the middle of each room stands a monstrous monolith whose color is not fixed, but changes regularly every forty two seconds.
Like most inhabitants of the universe, I have…
drorzel | November 5, 2007Dave Bacon has been assimilated. He only has one post up at the moment, but I'm sure there'll be more soon. Update your bookmarks and RSS readers, and go visit his new digs.
drorzel | November 5, 2007I'm suffering muscle twinges in my neck and shoulder that are usually linked to excessive typing. As I have a grant proposal to review, a senior thesis to help whip into shape, and a book under contract, this means that blogging will be substantially reduced while I ration my typing to those things that pay the bills. You'll get more linking and less thinking, at least until my shoulder calms down a bit.
I don't want to pass up a set of links-- two press releases and a news story-- on some new results regarding friction:
If you want to reduce the friction between tiny objects, just increase…
drorzel | November 2, 2007In the same basic spirit as the previous post, but with a physical science slant:
What items should be on the list for a scavenger hunt through an academic physics department?
The idea here is to keep a big group of grad students occupied and entertained for an afternoon by having them find items characteristic of academic physics research, such as:
One working piece of apparatus powered by vacuum tubes
One obviously broken piece of apparatus being kept "for spare parts"
One obviously broken piece of apparatus being kept for no apparent reason
One piece of computer software that's at least…
drorzel | October 30, 2007In today's New York Times Natalie Angier has a nice story about increased interest in physics:
Many people wring their hands over the state of science education and point to the appalling performance of America's students in international science and math competitions. Yet some of the direst noises about our nation's scientific prospects may be premature. Far from rejecting challenging science courses, students seem to be embracing them.
This year, for example, the American Institute of Physics said that the percentage of high school students taking physics courses was at an all-time high,…
drorzel | October 30, 2007I've never been one for costumes, but if you lean that way, and still don't know what you're going as tomorrow, Jennifer Ouellette offers some physics-themed Halloween costumes: Schrödinger's Cat, Maxwell's Demon, and BEC:
If you're looking for something a bit less mainstream, how about dressing up as a Bose-Einstein condensate this Halloween? That's what happens when a cloud of atoms in a gas get so cold -- practically down to Absolute Zero -- that they behave like one giant superatom. I'm not entirely sure how this would work; a bit of creativity is required. But it'd be a great idea for a…
drorzel | October 28, 2007On Thursday last week, the Schenectady weather forecast I have in my Bloglines feed called for "Tons of Rain," which I thought was amusingly unprofessional. I mentioned this to Kate yesterday (after it had, in fact, rained quite a bit), and she said "I wonder how much rain you would need to make a ton?"
Being a physics nerd, of course I had to try to come up with an answer.
We know that one cubic centimeter of water has a mass of one gram, so a (metric) ton of water would be 1,000,000 cubic centimeters, or one cubic meter. Our yard is about 20m x 50m, so if rain covered our yard to a depth of…
drorzel | October 28, 2007The Times today has an article on famous scientists who have nutty ideas, inspired by the James Watson kerfuffle of the last couple of weeks. Of course, they had to mention at least one kooky physicist, leading to this wonderful set of paragraphs:
Sometimes the wandering from one's home turf extends all the way to the paranormal. In 2001, when officials of the Royal Mail, the British postal service, issued a package of stamps commemorating the centenary of the Nobel Prize, they sought the counsel of Brian Josephson, who shared the prize for physics in 1973 for his superconductivity research.…
drorzel | October 27, 2007Via Physics Buzz, a Mechanical Aptitude Test for diesel technicians. It's fifty basic physics questions, covering a wide range of material from introductory physics: basic concepts of force and torque, a little bit of electrical circuits, and even some thermodynamics.
I got 45/50, which is a passing score. I suspect that I bombed the handful of questions involving specific engine terminology, because I know as much about cars as I do about 11-dimensional superstring theory.
Somebody needs to sit down with the authors and explain how units work-- forces are not measured in kilograms-- but…
drorzel | October 26, 2007Over at Neurophilosophy, Mo links to an article by a physicist, posted on the arxiv, that claims to explain visual perceptions using quantum mechanics:
A theory of the process of perception is presented based on von Neumann's quantum theory of measurement and conscious observation. Conscious events that occur are identified with the quantum mechanical ``collapses'' of the wave function, as specified by the orthodox quantum theory. The wave function, between such perceptual events, describes a state of potential consciousness which evolves via the Schr\"odinger equation. When a perceptual…
drorzel | October 22, 2007A little while back, Popular Mechanics published a list of 25 Skills Every Man Should Know. Seven of the 25 are car-related, another four have to do with construction, and an additional six are outdoorsy things. Of course, they also threw in "extend your wireless network," for the nerds out there, but it does tend toward the parodically ManlyMan side of things.
In response, Cut to the Chase posted a list of 20 "practical skills every self-sufficient adult should have", which probably errs in the other direction, with entries that are far too humorlessly sensible. (Though I notice that "Know…
drorzel | October 19, 2007An anonymous donor cashes in a $30 donation to ask:
Homework solutions from intro physics through grad school physics are available online, and while working through Jackson and Goldstein problems can be miserable without some guidance, the temptation is there to plagiarize. When you teach, do you use book-problems or write your own? Do you trust that those who are really interested in the subject will do the right thing and slog through homework like thousands before them?
An excellent question.
Homework is really a vexing issue. There's no way to really learn physics without doing…
drorzel | October 9, 2007Having gotten that silly Medicine business out of the way, the Swedish Academy has moved on to the important Award, with the 2007 Nobel Prize in Physics going to Albert Fert and Peter Grunberg for the discovery of Giant Magnetoresistance. This is one that people have been calling for for a while, now.
I'll try to give a more complete explanation of what this is and why it's important later, but I'm going to Boston with a student group today, and I need to run to catch the bus. I'll just note quickly that this should be applauded by blog readers, because GMR is an enabling technology for…
drorzel | October 8, 2007I somehow managed to lose track of time for a bit, and forgot that it was Nobel season until I saw this morning's announcement that the 2007 Nobel Prize in Medicine hase just been announced, going to Mario R. Capecchi, Sir Martin J. Evans, and Oliver Smithies,
for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells
Good thing they got the Nobel, because that sounds like the sort of icky, un-Godly work we wouldn't want to actually, you know, fund.
Anyway, the announcement of this prize means that the rest of the Nobels will be…