Physics
drorzel | May 10, 2007I'm sitting at the computer typing, when the dog bumps up against my legs. I look down, and she's sniffing the floor around my feet intently.
"What are you doing down there?"
"I'm looking for steak!" she says, wagging her tail hopefully.
"I'm pretty certain that there's no steak down there," I say. "I've never eaten steak at the computer, and I've certainly never dropped any on the floor."
"You did in some universe," she says, still sniffing.
I sigh. "I'm going to move the quantum physics books to a higher shelf, so you can't reach them."
"It won't matter. I've got Wikipedia."
"All right,…
drorzel | May 9, 2007The Zeitgeist for today highlights a little New York Times Q & A piece on atomic clocks, answering the question "Why is cesium used in atomic clocks?"
The striking thing about this, to me, is that they don't really answer the question. I mean, they talk about how atomic clocks work in very vague terms (I explained atomic clocks last August, in more detail), but the only thing they have on the "why cesium?" question is this:
It so happens, the United States Naval Observatory explains, that cesium 133 atoms have their 55 electrons distributed in an ideal manner for this purpose. All the…
drorzel | May 8, 2007One of the other ScienceBloggers is prone to complaining in the back-channel forums that we don't have enough bloggers who work in some subfield of biology or another-- we need more left-handed shrew ecologists, or some such. This is, of course, patently ridiculous. What we need is a physics blogger from the condensed matter world, so we'd have somebody to explain what's up with "supersolid" helium:
Superfluidity was discovered in the liquid phase in 1938, when Pjotr Kapitsa - who shared the 1978 Nobel prize for the work - found that liquid helium-4 suddenly behaves as if it has zero…
grrlscientist | May 4, 2007tags: Venus flytrap, plant, biology, mechanics
A Venus flytrap lies open, waiting for an insect to set off its trap. Lakshminarayanan Mahadevan and colleagues have shown that the plant uses stored elastic energy to operate its hinged leaves.
Image: Yoel Forterre.
How does the venus flytrap accomplish what most people cannot? How does a mere plant capture live flies? The mystery of the Venus flytrap's rapid movement lies in storing and releasing elastic energy, says Lakshminarayanan Mahadevan, who is the Gordon McKay Professor of Applied Mathematics and Mechanics at Harvard University.…
drorzel | May 4, 2007We were talking about student recruitment the other day, as faculty are wont to do, and our chair suggested that we really ought to have a "Why You Should Major In Physics" page as part of the department web page. As I'm currently the web page coordinator, it will fall to me to write whatever goes on that page.
Now, there's a fair bit of material out there about potential careers and stuff like that from the American Institutes of Physics and other sources, but that tends to be pretty dry. So I thought I'd throw this out to the physics blogosphere:
Why should students major in physics?…
drorzel | May 1, 2007I wrote yesterday's post about the undergraduate research study very quickly, basically just to note the existence of the survey. It's sparked some good discussion, though, and I'd like to take another post or two to expand on what I think it means.
Of course, the beneficial effect of undergraduate research seems almost obvious if you stop to think about it a bit. Undergraduate research works to attract students from all different backgrounds into science for a very simple reason: doing research is nothing at all like the typical science class.
OK, I can really only speak for physics, here,…
jstemwedel | April 26, 2007An important part of the practice of science is not just the creation of knowledge but also the transmission of that knowledge. Knowledge that's stuck in your head or lab notebooks doesn't do anyone else any good. So, scientists are supposed to spread the knowledge through means such as peer reviewed scientific journals. And, scientists are supposed to do their level best to make sure the findings they report are honest and accurate.
Sometimes, scientists screw up. Ideally, scientists who have screwed up in a scientific communication need to set the record straight. Just what is involved…
drorzel | April 22, 2007The highlighted article in Friday's Physical Review Letters is something Peter Woit has been going on about for months: "Cancellations Beyond Finiteness in N=8 Supergravity at Three Loops". It's been on the ArXiv for ages, but I'm old school, and don't think of papers as real until they're actually released in peer-reviewed journals.
The thing is, I'm really not sure what this means. That is, I know what the paper is about, but I'm not sure what the implications are.
My extremely limited understanding is that "N=8 supergraviy" is one of the early attempts at creating a theory of quantum…
drorzel | April 22, 2007I've seen several people link to the Scientific American piece on how to make your own "quantum eraser" experiment, which also includes a list of components and a detailed set of instructions, with pictures. There's a great "living in the future" kick to an article which assumes that you just have a laser lying around the house, and the basic demo is pretty cool.
The one quibble I have with this is that I think it's a bit of a stretch to call this a "quantum eraser."
The basic scheme here is that you take a laser, and diffract it off a small solid object taped between two perpendicular…
drorzel | April 19, 2007It's Decision Season in academia.
Across the country, high-school students are losing sleep at night worrying about where to go to college next year. We've had our annual Accepted Students Open House days (the second was Monday, with the turnout significantly reduced by the bad weather), at which we meet with students who are considering coming to Union, show them around, and try to talk them into coming here next fall. Our chairman desevres a special award of merit for the effort he puts in-- in addition to going to the massive all-campus lunch, and talking to students there, he'll conduct…
drorzel | April 18, 2007I've got another long lab this afternoon, so I'm stealing an idea for an audience-participation thread from James Nicoll:
Name five things we didn't know in the year that you were born that make the universe a richer place to think about.
This is actually a really interesting exercise for showing how rapidly the world has changed in the last N years. I'm not all that old-- to put it in pop-culture terms, the Beatles broke up before I was born-- but when I try to think about the landscape of science since then, it's astonishing how much the world has changed:
My own field of laser cooling,…
drorzel | April 16, 2007The big physics news of the week last week came while I was in transit on Wednesday: The MiniBooNE (the odd capitalization is because it's sort of an acronym) neutrino experiment released their first results on the neutrino oscillation studies they've been doing, and found, well, nothing new. In contrast to a previous experiment that hinted at the possible existence of a fourth type of neutrinos, the MiniBooNE results were entirely consistent with having only the three previously known types. There's a news article here, and one of the MiniBooNE experimenters did a excellent guest post…
drorzel | April 10, 2007I forgot to link to Sunday's New York Times article about D-Wave and their controversial claim to have made a working quantum computer, which prominently features quotes from the world's second funniest physics blogger:
Scott Aaronson, a theoretical computer scientist at the Institute for Quantum Computing at the University of Waterloo in Canada, fired the first shot. He wrote in his much-read blog, called "Shtetl-Optimized," that Orion would be as useful at problem-solving as "a roast beef sandwich." In an e-mail message to me, Dr. Aaronson denounced Orion as "hype." He said that he could…
drorzel | March 31, 2007As you undoubtedly already know, the Large Hadron Collider suffered a setback this week:
The start-up of the Large Hadron Collider (LHC) at CERN could be delayed after three of the magnets used to focus and manipulate the accelerator's proton beams failed preliminary tests at CERN earlier this week. The magnets were built at Fermilab in the US, which announced the failure on its Web site. Although CERN has not yet issued a formal statement on the set-back, it looks increasingly unlikely that the LHC will come on-line this year as planned.
(See also the official Fermilab release on the…
drorzel | March 31, 2007Just a quick note that everybody's favorite physics-oriented blog carnival is now up: Philosophia Naturalis #8.
Once again, I forgot to submit anything, but Sujit was kind enough to include one of the things I wrote anyway. There's a lot of good stuff there, so go check it out.
drorzel | March 29, 2007Steve Gimbel at Philosopher's Playground is calling for the abolition of lab classes:>p>
As an undergrad I majored in both philosophy and physics and I have a confession my former physics profs will surely not like -- everything I know about physics, I learned from my theory classes. You see, science classes come in two flavors. There are theory classes where a prof stands in front of the room and lectures and then there are lab classes where for many hours, students walk in ill-prepared and tried to figure out which one of these things we've never seen before is a potentiometer, fumble…
evolvingthoughts | March 27, 2007
Here is a list of Basic Concept posts in Physics and Astronomy.
Recently Added: Phase changes, by Janet Stemwedel at Adventures in Science and Ethics; De Broglie Equation (quantum physics) by Wandering Primate; Understanding Electricity by Scott Aaronson at Shtetl-Optimized; Ohm's Law by Chad Orzel at Uncertain Principles; Estimation and DImensions by Chad Orzel at Uncertain Principles
Energy by Chad Orzel at Uncertain Principles
Fields by Chad Orzel at Uncertain Principles
Force by Chad Orzel at Uncertain Principles
Measurement by Chad Orzel at Uncertain Principles
Entropy by Rob Knop…
drorzel | March 27, 2007There's a meeting now underway in London on Outstanding Questions for the Standard Cosmological Model, which is the term for the current Big Bang/ Inflation/ Dark Matter/ Dark Energy/ Accelerating Universe view of the history of the universe. Tommaso Dorigo is attending, and reports on the talks on his blog (and also a description of lively debate).
Some people would probably deride this whole meeting as a waste of time-- I know where I'd look if I were interested in finding an example-- but I think it's great that somebody's doing it. The ideas listed on the slide pictured in one of those…
drorzel | March 23, 2007Via Bookslut, there's an article in the Chronicle of Higher Education about whether reading is really important:
Is it always a good thing to read an entire book? When I was a graduate student, it dawned on me that I often had the most intelligent things to say about books I'd only half- or quarter-read. I was surprised by my observation -- it didn't seem to make sense. But it just seemed to work out that professors preferred my insightful and trenchant comments on, say, the first part of Tristram Shandy than on the whole wandering thing.
In that way, a little knowledge can be a practical…
drorzel | March 23, 2007The case of Purdue's Rusi Taleyarkhan, cleared by the university of charges of misconduct in a murky process, has taken another turn. Congress is getting involved, with the Investigations and Oversight Subcommittee of the House Science and Technology Committee requesting more details from the university.
On the one hand, I'm not enthusiastic about Congress getting into this (aren't there some drug-using professional athletes that they could investigate?), but then again, Purdue brought it on themselves with their ridiculously cryptic statements about the case. If they hadn't acted like they…