Physics
drorzel | August 9, 2010As seen in yesterday's post, SteelyKid got a grill this weekend:
This led to one of the cutest toddler anecdotes to date, which I'll put below the fold for the sake of those heartless souls who don't like cute kids.
SteelyKid was running around with an ice cube in a paper cup, because ice is pretty neat, and Kate's mom asked what she had. SteelyKid sumped it out into her hands, and Kate's mom said "Oh, that's cold."
SteelyKid replied "I warm it up," took the ice cube back, put it in the paper cup, put the cup on her toy grill, closed the lid for a few seconds, then brought it back. "Warm it…
drorzel | August 9, 2010So, last week, I talked about how superconductors work, and I have in the past talked about the idea of making cold atoms look like electrons. And obvious question, then, whould be:
Do cold atoms systems allow us to learn anything about superconductivity? The answer here is, unfortunately, "Yes and no."
That's pretty weaselly, dude. Yeah, well, there's nothing I can do about that.
There are a huge number of experiments out there using ultracold atom systems to look at Bose Einstein Condensation, which is related to superconductivity, and that transition has been studied in great detail. Those…
drorzel | August 9, 2010the hot topic in mathematical sciences at the moment is the draft proof that P≠NP (warning: PDF). This is one of the biggest issues in computer science, and one of the Clay Mathematics Institute's Millennium Problems, so a proof would be Big News in math/CS, and earn the prover a cool $1,000,000. Reaction among blogging theorists is mixed, with some intrigued and at least one willing to bet against it.
So what do I think of the proof? Honestly, this is so far out of my areas of competence that I need Google to remind me what the symbols mean. About all I know is that it's a Big Deal in…
rallain | August 7, 2010I have seen several videos similar to this.
Real? Fake? How many tries did this take? Let the analysis begin. Before I do any analysis, let me state that I think this is not fake. I do not know that for sure, just my first guess.
How would I tell if it is real or fake? This is tricky. I can't really get a good trajectory of the ball to make some measurements on it because of the camera angle (next time people, make sure you set the camera up perpendicular to the plane of motion and far enough away to avoid perspective problems - thanks!) Really, the best I can do is to look at the…
cevans | August 6, 2010
Let's talk about the God Particle.
It strikes me that people refer to the Higgs boson as the "God particle" in the same way some call the iPhone the "Jesus phone": with an almost pointed disregard for what such a prefix actually means. Considering the intensity of the culture wars, the popularity of the moniker is baffling. Is this about contextualizing the abstraction (and grandeur) of particle physics in a way "regular" people can understand? Does this represent a humanist concession to the religious? If so, can religious culture really be swayed by such a transparent ploy -- y'know, it…
drorzel | August 6, 2010In comments to yesterday's post about my favorite Many-Worlds story, a couple of people mention "All the Myriad Ways," a Larry Niven short story. I don't think I've ever actually read the story, but it gets brought up all the time, so I'm familiar with the concept. It's an angle on Many-Worlds that I don't like, and has something in common with the central conceit of Inception, which is also not high on my list of literary tropes, though my reaction isn't anywhere near as negative as Scott's.
If you're not familiar with it, here's the summary from Wikipedia:
A police detective, pondering a…
rallain | August 5, 2010This is a classic problem. You are in a car heading straight towards a wall. Should you try to stop or should you try to turn to avoid the wall? Bonus question: what if the wall is not really wide so you don't have to turn 90 degrees?
Assumption: Let me assume that I can use the normal model of friction - that the maximum static friction force is proportional to the normal force. Also, I will assume that the frictional coefficient for stopping is the same as for turning.
Stopping
I am going to start with the case of trying to stop. Suppose the car is moving towards the wall at a speed…
drorzel | August 5, 2010Today, Tor.com has posted the complete story "Divided by Infinity" by Robert Charles Wilson. This remains probably the best science fiction story ever using the Many-Worlds interpretation of quantum physics (though it doesn't call it that explicitly), and also the creepiest:
In the year after Lorraine's death I contemplated suicide six times. Contemplated it seriously, I mean: six times sat with the fat bottle of Clonazepam within reaching distance, six times failed to reach for it, betrayed by some instinct for life or disgusted by my own weakness.
I can't say I wish I had succeeded,…
drorzel | August 5, 2010A reader emailed me with a few questions regarding How to Teach Physics to Your Dog, one of which is too good not to turn into a blog post:
What is a photon from an experimental perspective?... Could you perhaps provide me with a reference that discusses some experiments and these definitional issues?
The short form of the experimental answer is "A photon is the smallest amount of light that will cause a detector to 'click.'" (For some reason, hypothetical light detector technology has never really advanced past the Geiger counter stage-- even though it's all electrical pulses these days, we…
drorzel | August 4, 2010On the reader request thread, commenter Brad had several questions; one led to yesterday's post about superconductors, another is a critical issue in pedagogy:
Finally, why did all of my stat[istical] mech[anics] courses suck?
Statistical Mechanics is the branch of physics that deals with building up macroscopic thermal properties of materials from a microscopic model of gas atoms with particular energy states. It's an important and powerful branch of physics dealing with things like the melting and freezing of various substances, and why entropy always increases, and things like that. It's…
rallain | August 4, 2010First off, I think this is a really good post (not this self-referring post, but the post I am about to link to)
Steak Dinner by Alemi at The Virtuosi
In short, this post is about cooking steak and the measurements of the temperature of the meat. Why do I think this is a good post?
First, it is just some ordinary everyday event (well, it's not everyday you get steak). The awesomeness just comes from saying "hey, maybe I should plot this temperature data".
If the post was just about plotting data, it wouldn't be terrible. But it does something else. It tries to fit this data to some sort…
drorzel | August 4, 2010I had the tab open and everything, and still somehow forgot to include a link to John Baez's blog post reporting on a talk by Tony Leggett which directly addresses some of the questions asked about yesterday's superconductivity post. It's about a talk called "Cuprate superconductivity: the current state of play" ("state of play" apparently being a favorite phrase of Leggett's), and directly addresses what's weird about high-temperature superconductors and why they haven't been explained theoretically.
These are notes from a talk, and thus somewhat compressed, but it's a good summary of the…
rallain | August 3, 2010I am seriously late on this stuff. First, by clickers I mean student response systems. In a previous post, I stated how much I like these things. The basic idea (in case you have never heard of them) is that these are small devices that students in a class have. The instructor (learning facilitator) presents some multiple-choice questions and the students click a button to represent their answer. The summary of the student responses can then be presented to the class.
Big whoop you might say. But it is a big whoop and here is why:
Technologically and logistically, these are trivial to…
drorzel | August 3, 2010In the reader request thread, Brad asks about superconductors:
Why is a room temperature superconductor so hard? Why do things have to be cold for there to be no resistance (I can guess, but my knowledge of super conductors consists of the words "Cooper pairs" which does not get me very far.)
Since next year will mark 100 years since the initial discovery of superconductivity in mercury by Heike Kammerlingh Onnes, this is a good topic to talk about. Unfortunately, it's a bit outside my field, but I can give you what I know from my not-much-better-than-layman's understanding of the field, and…
rallain | August 2, 2010
Try to say that 5 times really fast. Go ahead, try it. Well, at least it is not as difficult as Fox in Socks - man that book is a killer.
This WAW is basically a means to embed Wolfram Alpha queries into a webpage. Pretty cool idea, but I am not sure how well it does the job. In fact, I have tried to embed calculations in my posts before. So, how about I just give a quick review of some different ways to do this. For all these methods, I will put in a calculator to determine the density of something given its mass and volume.
Javascript version
Density calculator
Enter the mass:
kg…
ksnyder | August 2, 2010Silk taffeta, flowing gowns, sheaths, and...a lab coat? It may sound like a fashion faux pas, but these were the makings of NYC-based designer Shin Choi's spring 2000 collection.
At $378, this lab coat should probably be saved for the most special occasions
That season's catalogue, which recently ended up on my desk after a coworker's office-cleaning session, featured a fitting backdrop: intriguing scientific scenes at Brookhaven Lab. Alongside the slender model stands bulbous cryogen tanks, an abandoned bubble chamber, and widgets and gadgets galore.
This shot was taken next to a set of…
drorzel | August 2, 2010Thoreau at Unqualified Offerings gets credit for inspiring two posts today with his proposed Murphy's Law experiment and this one, about an unrelated issue in quantum measurement. This is an analogy suggested by a colleague a couple of years ago, comparing the projection of a quantum wavefunction in the measurement process to the lottery.
The classic example of this problem is something like the double slit experiment with single particles. You have some position-sensitive detector that we can imagine as being made up of a large number of pixels, each having some probability of detecting a…
drorzel | August 2, 2010Over at Unqualified Offerings, Thoreau proposes an an experimental test of Murphy's Law using the lottery. While amusing, it's ultimately flawed-- Murphy's Law is something of the form:
Anything that can go wrong, will.
Accordingly, it can only properly be applied to situations in which there is a reasonable expectation of success, unless something goes wrong. The odds of winning the lottery are sufficiently low that Murphy's Law doesn't come into play-- you have no reasonable expectation of picking the winning lottery numbers, so there's no need for anything to "go wrong" in order for you…
drorzel | August 2, 2010Avi Steiner emailed me with a set of questions that are too good not to turn into a blog post:
Being a math/science major at a small liberal arts college, I unfortunately never get the "full" experience of a math/science talk. Since I do plan on eventually attending grad school, I thought it might be beneficial to get an idea as to what the aforementioned "full" experience is. Therefore, I present to you and your readers the following questions:
1. At what point in a group's/individual's research will they choose to give a talk?
2. What sort of questions are asked?
3. Are there any recurring…
drorzel | July 31, 2010A lot of Twitter energy was soaked up Friday afternoon by a half stupid article by Virginia Heffernan at the New York Times. Sparked by Sodamageddon, she takes a look at ScienceBlogs for the first time, and doesn't like what she sees:
Hammering away at an ideology, substituting stridency for contemplation, pummeling its enemies in absentia: ScienceBlogs has become Fox News for the religion-baiting, peak-oil crowd. Though Myers and other science bloggers boast that they can be jerky in the service of anti-charlatanism, that's not what's bothersome about them. What's bothersome is that the site…