drorzel | January 27, 2006This is true.
A guy I knew in graduate school, he had a buddy who was working late in the lab one night. He was all alone, and he got a little bored, so he took a two-liter soda bottle, and he filled it halfway up with liquid nitrogen. Then he screwed the cap on tight.
Now, liquid nitrogen, when it boils, it takes up something like 700 times the volume of the liquid. So this guy, he's got this bottle, and he's kicking it around in the hall. But the bottle starts to swell up, so he tries to open the cap, and it's stuck. So he runs into the bathroom, and he dumps it in a sink, and runs back out…
drorzel | January 27, 2006Next up in the Top Eleven is an experiment whose basic technique is still in use today.
Who: Henry Cavendish (1731-1810), a British scientist who made a number of discoveries in physics and chemistry, but received credit for very few of them.
When: 1797.
What: Cavendish's modern claim to fame is the torsion pendulum experiment, an idea that originated with John Michell, who died before completing it.
The apparatus for the famous experiment, shown at left, consists of a dumbell-shaped pendulum hung from a very fine wire. Two larger masses (Cavendish used 350 lb lead spheres) are brought near…
drorzel | January 25, 2006Some interesting astrophysics news this week, from Nature: scientists have used "microlensing" to discover a extrasolar planet only five times Earth's mass:
Planet OGLE-2005-BLG-390Lb looks much more like home. It lies about 390 million kilometres from its star: if it were inside our Solar System, the planet would sit between Mars and Jupiter.
It takes ten years for the planet to orbit its parent star, a common-or-garden red dwarf that lies about 28,000 light years from Earth, close to the centre of our Galaxy.
Of course, it's not quite time to start buying tickets for the colony ships: at…
drorzel | January 25, 2006Third in the Top Eleven is Sir Isaac Newton, who squeaks in with two nominations for two different experiments.
Who: Isaac Newton (1642-1727), famous English physicist, mathematician, alchemist, Master of the Mint, and Neal Stephenson character.
When: Newton was secretive and reluctant to publish anything, so it's sort of hard to assign dates. I'm going with "About 1700."
What: Newton pretty much kicked off modern science, so you could go on for a long time about his various accomplishments, but he was cited for two specific experiments: splitting white light with a prism, and measuring the…
drorzel | January 25, 2006The second in the Top Eleven is the first quantitative measurement of the speed of light, by Ole Christensen Roemer (whose last name ought to contain an o-with-a-slash-through-it, that I've rendered as an "oe").
Who: Ole Roemer (1644-1710), a Danish astronomer.
When: The crucial observations were made around 1675.
What: Roemer made careful observations of the orbit of Jupiter's moon Io (which circles the planet once every two days or so), and noted that the time between eclipses of Io (times when it disappeared behind Jupiter) got shorter as the Earth moved closer to Jupiter, and got longer…
drorzel | January 24, 2006The first and oldest of the experiments in the Top Eleven is actually a two-fer: Galileo Galilei is nominated both for the discovery of the moons of Jupiter, and for his experiments on the motion of falling objects.
Who: Galileo Galilei (1564-1642), the great Italian physicist, astronomer, and general Renaissance man.
When: He's known to have made the first observations of the moons of Jupiter around 1610. The dates of the experiments on accelerated objects are fuzzier, but around the same time.
What: Shortly after obtaining a telescope (after its invention by Dutch astronomers), Galileo…
drorzel | January 24, 2006Evil elves have apparently snuck into the house in the middle of the night, and stuffed my sinuses with cotton and motor oil (the dog is sitting here muttering "I told you there were evil elves out there but did you listen? 'Stop barking at nothing,' you said..." Or maybe that's the drugs.). This sort of cuts down on my ability to think Deep Thoughts and post the results here.
I can, however, carry out mechanical tasks like tallying the nominations for the Greatest Physics Experiment (to go with Clifford's Greatest Physics Paper on the theory side). The list of experiments mentioned by at…
drorzel | January 23, 2006Thursday night, I needed to work late, so rather than upset the dog by going home for dinner, and then leaving, I went for sushi at a local restaurant. I had a very pleasant meal, which I spent reading through the first few chapters of the textbook I plan to use for my Quantum Optics class next term (to make sure it will work for my purposes), and listening to the woman at the table next to me talk to her kids (ages 7 and 9, and cutely overactive).
Eventually, the kids wandered off to go pester the sushi chef (they're apparently regulars), and their mother asked me "What is it you're reading…
drorzel | January 22, 2006It's depressingly typical of my life that we would get BoingBoing-ed on a weekend when I'm visiting the in-laws...
I've gotten a bunch of responses to my earlier request for "Great Experiments" in other areas of science, and I thought I'd collect the links in one post (many of them show up as TrackBacks to the original post, but some don't):
RPM's list of Best Biology Experiments/Discoveries on Evolgen.
Razib at Gene Expression offers another set of biology discoveries.
Dave and Greta Munger agree on a single great cognitive science experiment (with nifty graphics!)
Tara at Aetiology lists…
drorzel | January 21, 2006We've had an outbreak of mathematician jokes in comments, so it seems only fair to offer up a thread for the mockery of physics. Sadly, there really aren't many good physicist jokes. My personal favorite:
A physicist, a chemist, and a biologist get together for a few drinks, and get to talking about life, the Universe, and everything. Eventually the conversation turns to relationships, and what the ideal way to arrange relationships between the sexes would be.
The biologist says "Well, as a believer in evolution, I feel that every person should sleep with as many other people as possible, in…
drorzel | January 21, 2006I probably ought to say something about the New York Times piece on ScienceBlogs yesterday, except, well, there's not much to say. It's about two paragraphs in a media column, focussed entirely on the fact that they're going to try to sell ads on these sites (presumably, the big Seed ad on the right will become an ad for SigmaPlot, or something...). It doesn't really mention the content of the sites, except in passing.
(The article does continue the fine tradition of the New York Times writing articles about organizations I'm associated with without mentioning my name...)
I do want to…
drorzel | January 20, 2006Over at Gene Expression, Razib spins an interesting question off my call for blog posts: why are there so many biology bloggers?
As I said in comments over there, I think there are two main reasons why you find more bio-bloggers than physics bloggers. The first is that there are simply more biologists than physicists-- we're expecting an unprecedented 13 senior physics majors next year, which is forcing some frantic re-organization to handle the load, but a class that small would be a major crisis for the Biology department. The second reason is that biology is really the main front of the "…
drorzel | January 19, 2006In the ongoing string theory comment thread (which, by the way, I'm really happy to see), "Who" steps off first to ask an interesting question:
One way to give operational meaning to a theory being predictive in the sense of being empirically testable is to ask
What future experimental result would cause you to reject the theory?
I think what worries a lot of people about string thinking is that it seems so amorphous that it might be able to accomodate any future experimental measurement. In fact I am not aware of any string theorist's answer to this basic question.
It's an interesting…
drorzel | January 18, 2006I'm giving an exam this morning, and I've got some oral lab report presentations to listen to this afternoon, plus I need to put together some Mathematica activities for Friday. This doesn't leave great deal of time for detailed science blogging, so here are some pop song lyrics, courtesy of the four-and-five-star playlist on iTunes.
1) "Do we see what the clock makes you do/ But I won't let this happen to you"
2) "You got the hair slicked back, and those Wayfarers on, baby"
3) "Like my loafers? Former gophers. It was that, or skin my chauffeurs."
4) "Now we're gonna be face-to-face/ And I'…
drorzel | January 17, 2006Newton's Principia has won the prestigious Cosmic Variance Greatest Paper contest, with Dirac's theory of the electron coming in second. I'm still accepting nominations for the greatest physics experiment ever (probably until the weekend, when I'll have time to do something with the list...).
Thinking about this, it occurs to me that this might be a good topic for some cross-ScienceBlogs discussion, if any of my co-bloggers are interested. I've got a decent idea of what the great experiments in physics are, but I'm pretty hazy on what would be considered the short list in the other fields we…
drorzel | January 17, 2006There was a postdoc in my research group in grad school who had a sister in college. She called him once to ask for help with a math assignment dealing with series expansions. He checked a book to refresh his memory, and then told her how to generate the various series needed for her homework assignment.
A week or so later, he asked how she'd done. "Terrible," she said. It seems that he had just plunged ahead with generating series terms without doing the convergence tests and other proofs that a mathematician would do for the same problems. She told him, "My professor said I answered all the…
drorzel | January 16, 2006Today is the last day to vote in Cosmic Variance's Greatest Physics Paper contest. If you haven't voted yet, go over there and pick a paper.
Locally, I'm still collecting nominees for the Greatest Physics Experiment. A quick scan through the comments gives the current list as:
The Michelson-Morley experiment disproving the aether.
Rutherford's discovery of the nucleus.
Aspect's Bell Inequality test.
Galileo's inclined planes, or possibly the discovery of the moons of Jupiter.
The Mossbauer Effect.
If you have a favorite physics experiment, and don't see it on that list, go leave a comment…
drorzel | January 16, 2006There's a slightly snarky Review of Leonard Susskind's book on string theory (The Cosmic Landscape: String Theory and the Illusion of Intelligent Design) in the New York Times this week. Predictably, Peter Woit is all over it.
The central issue of the book, and the review, and Woit's whole blog is what's referred to as the "Landscape" problem in string theory. This is a topic that seems to consume a remarkable amount of intellectual energy for what's really a pretty abstract debate. It also leads to a remarkable amount of shouting and name-calling for something that just doesn't seem like…
drorzel | January 15, 2006I'll have something more serious to say on this subject tomorrow (I want to sleep on it, and take another look at the post in the morning), but I have one quick comment on the New York Times review of Leonard Susskind's The Cosmic Landscape:
Susskind's insider perspective also lends an air of smugness to the whole affair. He falls prey to the common error of Whig history: interpreting past events as if they were inevitable stepping stones to the present. He allows remarkably little doubt about string theory considering that it has, as yet, not a whit of observational support. "As much as I…
drorzel | January 15, 2006A while back, I talked about a colloquium where Steven Boughn of Haverford argued that it's practically impossible to detect a single graviton. It was a very nice talk, relying mostly on simple dimensional analysis arguments, and very basic physics.
Today, via Wolfgang Beirl (via Mixed States), I see that Boughn and Tony Rothman have a paper on the porn server about graviton detection. It's got a bunch more math, but the conclusion is the same.
It's a clever paper, and worth a look if you're into this sort of thing.