Tuesday, October 31, 2006

Fastest Waves Ever Photographed

Pictures of the fastest moving waves ever photographed were presented this morning at APS Division of Plasma Physics meeting in Philadelphia. These shots are more than your typical pretty pictures – they represent a major advance in wakefield accelerator technology, a technology that could make tabletop high-energy particle accelerators a reality.

The matter waves, which are oscillations moving through a plasma, are known as wakefields because they are created in the wake of an ultra-intense laser pulse. The waves travel at 99.997% of the speed of light and generate electric fields exceeding 100 billion electron volts/meter.

The ability to create huge electric fields makes wakefields a promising method for shrinking the size of accelerators from miles long (like those at the Stanford Linear Accelerator Center, FermiLab and CERN) to tabletop. Small accelerators would allow universities and hospitals to take advantage of the research and medical applications afforded by an accelerator without competing for time at a major particle accelerator facility.

Much work remains before tabletop accelerators can be a reality – particularly in understanding the interactions between a wakefield, the accelerated electrons, and the laser pulse. The ability to photograph wakefields is exciting news for scientists because it allows them to explore these interactions and compare theoretical predictions to real data.

Researchers from the University of Texas designed a holographic-strobe camera to take these pictures. Their method, called Frequency Domain Holography, sends two additional laser pulses though the plasma along with the ultra-intense pulse. The additional pulses detect the oscillations and then travel through a spectrometer where they interfere and are analyzed.

An abstract of the talk and a lay language paper describing the research are available online.

Read the rest of the post . . .

Tie One On

What do Mothers Against Drunk Driving, neckties, and microscopes have in common?
The Cocktail Collection of men's neckwear by Stonehenge, Ltd. of course!

Think about it - how better to market neckties to men than with a line featuring colorful images of crystallized beer (left) and scotch (right)? Now, turn that into a partnership with Mothers Against Drunk Driving and a catchy line such as "The only way to ‘tie one on’ before driving." Genius!

I am a little late in voicing my appreciation for this as the ties debuted in the early 1990s - but hey, I was only 12 at time.

Michael Davidson, a biochemist-turned-microscope artist, took the images for the ties through an optical microscope. His company (Molecular Expressions) now has a whole line of beer images, as well as images of vitamins, pesticides, birthstones, and all kinds of other things that adorn items from clothing to greeting cards (visit the Galleria).

In addition to being colorful and fun, the images are a powerful reminder that changing your perspective can make a big difference in what you see. Put a glass of Guinness Stout next to Davidson's microscopic image and you'll know what I mean. Science and art are both about seeing everyday things in a new way - and exploring that viewpoint.

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Monday, October 30, 2006

Smart Music for Smart People

Writer/song writer Jonathan Coulton took some time off of his book tour with John Hodgman to play some tunes at a conference for science writers I attended this weekend in Baltimore.

All things considered, good music is hard to find (how many bands form for every one that gets a music contract?), and so is funny music. How great is it when you get to hear songs that are both good and funny? Coulton is one of the rare musicians who can weave sophisticated, sexy, and funny lyrics into a tune you'd actually want to play just because it sounds good. (Are you listening Weird Al?)

His selection of tunes seemed tailored to appeal to the sort of people who go into science writing, primarily evoking images of supervillains, nerds and sysadmins railing against the iniquities of a world where their unique talents and delicate sensitivities are perpetually trampled by the unenlightened masses.

My favorite line of the night was from Skullcrusher Mountain, a ballad that gives listeners a glimpse of a supervillian in love.

Isn't it enough to known that I ruined a pony,
Making a gift for you?

You can listen to his music for free on his website. I haven't had a chance to listen to much besides the things he played for us, but I highly recommend Skullcrusher Mountain, Code Monkey, and The Future Soon.

Download the songs for keeps for a dollar a pop. Although the smiley faces next to some songs seem to indicate that he's giving those away for free.

My recommendation is download Skullcrusher Mountain while it's free. If you like it, buy a song or two to keep this guy in business.

And if you haven't clicked on the YouTube video above, you should take a moment to check it out. You'll develop a whole new respect for zombies.

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Friday, October 27, 2006

A virtual education?

(My apologies to those that saw the early version of this - I hit publish by mistake...)

The New York Times recently published an article on virtual science classes - in particular virtual science labs. The motivation for the discussion was the College Board's investigation into whether high school classes that use virtual labs can be AP classes.

The argument for accepting AP virtual lab classes is emotionally pulling: it gives students -- in rural high schools that don't have access to advanced lab equipment or that are taking classes online because their local high school doesn't offer them -- the opportunity to take AP classes. In addition, the article points out, students in online schools often earn high scores on the AP exam.

But I'm not sold on their argument. After all, the issue is not really about equal opportunities, but about how prepared students are for college classes. And college classes have physical labs. I think that half of the learning in science takes place because you had the chance (and took it) in the lab to do something WRONG the first time (or second...or third...).

I admit that I've never taken an online lab, but even if you can make mistakes and mess up virtual labs, I bet you can't break the voltmeter or throw the resistor across the room - both of which helped prepare me for college courses! In addition, students doing labs from home don't have the chance to build the group work skills that are often essential to hands-on lab success.

I'm not saying that students don't profit from and shouldn't take online lab classes; I just know that it would have been a lot harder for me to jump into to an advanced science class with no previous lab experience.

Read the rest of the post . . .

Wednesday, October 25, 2006

Tongue Display to Prevent Buttock Sores

A display device that transmits crude images to the tongue has been adapted to alert people suffering from sensory loss that they may have remained seated in one position for too long.

The system, developed by medical physicists at the Institut d'Informatique et Mathématiques Appliquées in Grenoble, France, includes a Tongue Display Unit (TDU) and a pressure sensitive pad placed under the buttocks. The TDU is a square array of 36 electrodes that can apply patterns of low voltage signals to the tongue.

The continuous pressure on one portion of the body that occurs when someone lies or sits still for long periods can lead to dangerous pressure ulcers, commonly called bedsores. The TDU in combination with the sensor pad is an attempt at sensory replacement - substituting one sensory signal for another - to reduce the incidence of pressure ulcers in people who are partially paralyzed or have lost sensory responses below the waist.

Although the system has only been tested in healthy subjects thus far, the researchers report a 92% success rate among 10 people asked to interpret TDU signals representing the front, back, left, or right portions of their buttocks. The ribbon cable attached to the TDU is unwieldy, but wireless versions currently in development could make the device more clandestine.

The research group is also developing TDU-based devices that may eventually guide the hands of surgeons. Other researchers have studied using TDUs as alternative to Braille, or to replace sight altogether

The article describing the TDU/buttock monitor was published July 12, 2006 in the French medical journal L'escarre.

An English language press release is available on the group's website

Read the rest of the post . . .

Student Happiness Overrated?

I always liked math - I was even on the math team in high school (although only for the cookies!), but I admit to having tortured geometry and trig teachers with the ever popular question:

"What does this have to do with real life?"

As a student I felt that the classes I took should be relevant to life. And I really appreciated teachers that made the materials engaging and fun. But did any of this really make my education better??

A recent study compared 8th grade math students across the world and found that countries that ranked in the top 10 in terms of math enjoyment all scored below average in math skills, while countries that ranked in the bottom 10 on the enjoyment level all excelled in skill level.

Read the above paragraph again: the study found that across countries math enjoyment is inversely related to performance.

"Countries with more confident students who enjoy the subject matter - and with teachers who strive to make mathematics relevant to students' daily lives - do not do as well as countries that rank lower on the indices of confidence, enjoyment, and relevance" (page 14 of the study).

The study (How Well Are American Students Learning?) was done by the Brookings Institution's Brown Center on Education Policy and analyzed data from the 2003 Trends in International Mathematics - a test taken by 4th and 8th graders across the world. Students answered math questions and rated their enjoyment of math, level of confidence, etc.

The authors point out that within a given country, the students with more confidence tend to outscore those with low confidence. They also point out that this study does not give cause and effect - nevertheless, it raises some interesting questions. Not least of which is:

Is it more important in the long run that students have a positive educational experience or that they learn the material???

Feel free to share your opinion.

Read the rest of the post . . .

Tuesday, October 24, 2006

Black Holes that are neither Black nor Holes

Stephen Hawking showed some time ago that black holes might actually emit light known as
Hawking radiation
, not from their bottomless interiors of course, but from the event horizon that marks the point of no return as you approach one of these monsters. In other words, black holes probably aren't black.

Now it seems collapsing masses that aren't black holes quite yet can bend space much as true black holes do, and give off the signature black hole Hawking radiation.

From a distance, such a thing would look just like a black hole, except that it wouldn't have a hole at the middle.

OK, OK, I can guess what you're thinking. Doesn't the lack of a singular point mass at the center mean it's not a black hole?

Hey, it still passes the duck test. After all, whether there is a hole at the center or not, I don't think any person or probe will ever be able to visit one and get back intact to tell us about it.

Carlos Barceló, Stefano Liberati, Sebastiano Sonego, and Matt Visser of the Astrophysics Institute of Andalucía in Granada, Spain predicted the unholey black holes. Because they can't actually check a gravitational black hole, they confirmed the mathematics of their theory by studying a simulation of fluid flowing down a narrow pipe. Once the speed of the fluid going down the drain passes the speed of sound in the fluid, the system acts just like a black hole, at least as far as sound getting sucked inside goes. The fluid analog even emits acoustical Hawking radiation from its acoustical event horizon.

The thing is, the fluid analog emits Hawking radiation slightly before it becomes a true acoustic black hole. The researchers believe a collapsing mass that is almost, but not quite, a black hole should give off Hawking radiation too.

Check out the APS Physical Review Focus story to get more information about theory that will be published soon in Physical Review Letters.

Read the rest of the post . . .

Monday, October 23, 2006

Crochet Math

A few months ago, we were fortunate enough to have a display of crochet art by Daina Taimina in the lobby of the American Center for Physics. The pieces sat in glass cases surrounding our rotunda. When I first saw them I had no idea what they were supposed to be, although some reminded me of the wood ear fungus on trees just outside the building. In fact, they were crochet examples of hyperbolic planes.

I confess that the whole idea of hyperbolic planes is a bit beyond me (the wikipedia page didn't help much, although now I know the word hyperparallel), even though the artist herself explained it to us at the art opening. But looking at Taimina's pieces certainly gave me an intuitive feel for the math. I only wish we had been allowed to pass them around to touch them and stretch them out a little.

I guess I'll have to make my own hyperbolic plane crochet toy to play with. Fortunately, the instructions are available in the book Taimina wrote with David Henderson. It's on the shelf at the University of Maryland library just down the road. Of course, first I'll have to learn how to crochet.

Those of you who already have mad crochet skills may understand this simple instruction on The Institute for Figuring page that shows lots of examples. "Taimina intuited that the essence of this construction could be implemented with knitting or crochet simply by increasing the number of stitches in each row. As you increase, the surface naturally begins to ruffle and crenellate." Increasing the count in subsequent rows by different numbers gives different shapes, apparently.

Check out the rest of Taimina's designs in her online gallery.

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Friday, October 20, 2006

dinner-party conversations...

I was paging through a book on temperature by the physicist Gino Segre today and noticed the first comment under the "Praise for A Matter of Degrees" section:

"Segre's informal style reads like a dinner-party conversation with a physicist." - The Washington Post

It got me thinking - what exactly do people think a dinner-party conversation with a physicist is like? Was the Washington Post's comment a compliment or a dig at the jargon-laden words we throw into even informal conversations?

I was shoe shopping at the mall with some friends a few years ago, having fun flirting with the salesman. He asked me what I was studying and I dropped the p-word. Big mistake. The conversation died on the spot. "Oh" he said, and then avoided me the rest of the time that I was in the store. Apparently he wasn't too interested in having a shoe-store conversation with a physicist, much less a dinner conversation.

I and many of my physicist friends have had the experience of telling someone that we study physics and immediately being asked, "What do you think about string theory? I saw this nova special..." While I applaud the program and the attention it brought to physics, I had (and still have) little knowledge on the subject and even less insight on it to offer. But it seems that many people think string theory is a popular subject for physicists to discuss not just at dinner, but on plane rides, in stores, and on buses.

Physicists are known for having quirks - just check out the travel tips and stories in the recent issue of Symmetry magazine. But I feel the need to point out that my dinner conversations rarely revolve around physics. Of course I "only" have a masters in physics - maybe if I were a full member of the physics community I would spend my evening meal discussing string theory and superconductivity instead of Lost or the recent Flogging Molly concert.

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Thursday, October 19, 2006

Physics Picture of the Week: Pretty Packing

At first glance, this translucent and intricate image struck me as being too pretty for the pages of a physics journal. If it weren't for the added letters and dotted lines, I might have though it was some abstract work of art.

It is actually part of an experimental study about the way things fold.
To generate the image, physicists at the Laboratoire de Physique Statistique de l’Ecole Normale Supe´rieure
in Paris pulled a mylar sheet through a hole and photographed it from below. They are hoping to learn more about the way flexible structures pack into small spaces.

The study could help us to better understand things such as the way flowers are folded in their buds just before they burst into bloom, the best way to compact trash, and how DNA wraps up in a cell nucleus.

The paper Spiral patterns in the packing of flexible structures by L. Boue´ et al. will be published online in Physical Review Letters tomorrow.

Read the rest of the post . . .

Wednesday, October 18, 2006

Single Pixel Camera

I was on the bleeding edge of digital photography when I bought my one megapixel camera back in '96. Now some physicists at Rice University in Houston have the nerve to build a ONE PIXEL camera. The camera produces images by recording thousands of single-pixel images one after the other, rather than simultaneously recording millions of pixels.

It's not the greatest camera in the world, as you can tell from the pictures you see here. The image on the left is a conventional close up photo of a Mandrill and the photo on the right is a single pixel camera shot of the same image. What’s more, it takes about fifteen minutes to record a shot like this with a single pixel. So it's not likely that you'll be standing in line at Circuit City with a single pixel camera in your cart any time soon.

The key benefit of the experimental camera is that it needs much less information to assemble an image. Massive CCD arrays collect millions of pixels worth of data, which are typically compressed to keep file sizes manageable. It's an approach the Rice researchers describe as "acquire first, ask questions later." Many pictures, however, have portions that contain relatively little information, such as a clear blue sky or a snowy white background. Conventional cameras record every pixel and later eliminate redundancy with compression algorithms.

The single pixel camera, on the other hand, compresses the image data via its hardware before the pixels are recorded. As a result, it's able to capture an image with only thousands of pieces of information rather than millions.

The compression is achieved with an array of tiny, movable mirrors. Various mirror arrangements encode information about the photographic subject as a whole, in lieu of the point-by-point image recording in a normal camera.

One potential payoff of this sort of research is that it may make conventional digital cameras much better. If a single pixel can do the job of an array of pixels, as the Rice University team shows, then you could potentially get each of the pixels in a megapixel camera to do extra duty as well. Effectively, you can multiply the resolution of your camera with the techniques developed in a single pixel camera.

The technology could make cameras much cheaper by letting us get by with fewer pixels, or perhaps lead (some day) to gigapixel resolution from megapixel cameras. In addition, the researchers say, the single pixel detector can be replaced with devices that register other wavelengths of light, potentially leading to images collected with light outside the ranges that CCD and CMOS detectors can handle.

You can peruse the paper that the researchers presented at the Optical Society of America meeting a few weeks ago in Rochester, New York, if you want all the details. For more readable information, visit their website or read the Physics News Update item my friends at AIP posted recently.

Read the rest of the post . . .

Tuesday, October 17, 2006

Getting a Grip on the World's Smallest Robotic Hand

The world's smallest robotic hand, which can make a fist that can grasp objects smaller than a millimeter across, has been developed by Yen-Wen Lu and Chang-Jin(CJ) Kim of UCLA's Mechanical and Aerospace Engineering Department .

The microhand hand has four fingers built of miniscule silicon segments and polymer-balloon joints, giving the hand a firm but gentle grip that the researchers claim would be ideal for manipulating tiny, delicate objects. In fact, in a (somewhat creepy) video on CJ Kim's website, they show a close-up of the microhand delicately plucking what appears to be a single fish egg from a glob of roe.

The hand opens and closes when the balloons in the joints are inflated and deflated. Because it is built of inert materials and is pneumatically rather than electrically operated, the microhand works well in air or liquid, making it handy (pardon the pun) for grasping small biological samples, which are often moist or in liquid environments.

Lu and Kim described their robot hand in the article Microhand for biological applications, which was published October 16 in the American Institute of Physics journal Applied Physics Letters.

Read the rest of the post . . .

Bats, brains, and larva snacks

Tis the season for costumes and pumpkins, carmel apples and witches, tricks and treats...and some of the coolest science!

Get in the mood by reading some real life spooky stories, such as Bats: Do they really suck blood , Secrets of the Mummy, or any of the stories linked to things that go bump in the night - all from the Why Files (a great science site).

Then check out Steve Spangler Science: Halloween Science Recipes for great ideas on how to make your own halloween props while learning all about the science behind slime, dry ice, and make-your-own quicksand. Be sure to watch his exploding pumpkin video - though note that he doesn't tell you how to do it yourself :(

And my guess is that nothing will get you in the mood for trick or treating like a big bowl of crunchy larva snacks (they come in BBQ, cheddar cheese or Mexican spice) or chocolate covered insects. Or a nice dish of jello shaped like a brain or an anatomical heart.

Tired of giving out the same kinds of candy every year? This year do something different - hand out scorpion, cricket, or larva lollipops. They're even sugar free!

Read the rest of the post . . .

Monday, October 16, 2006

Multiple Choice Makes Better Tests

All things considered, multiple-choice tests are better than tests that require students to work out extended problems with a pencil and paper, according to a study of physics undergrads at the University of Illinois, Urbana-Champaign.

While a comparison with longer format tests showed that multiple-choice questions are equally as good at evaluating students’ relative performance, there are significant added benefits to eliminating calculation-crammed test booklets. To be specific, multiple choice tests ease grading demands in large classes, reduce grading ambiguity and inconsistencies between graders, and dramatically cut back on the numbers of students contesting grades.

While standardized test questions for exams like the SATs and GREs undergo rigorous evaluations, the Illinois study focused on tests designed by instructors with little or no formal training in writing exam questions.

Nevertheless, the researchers conclude that multiple choice exams in the University’s physics classes

A) are just as reliable and valid as other types of tests in gauging students’ understanding of class material.

B) are as good or better than traditional format tests at assessing relative rankings of students in a class.

C) effectively eliminate student complaints about grading fairness.

D) all of the above.

(Answer: D)

The article by Michael Scott, Tim Stelzer, and Gary Gladding is in the journal Physical Review Special Topics – Physics Education Research. Like all of the articles in the APS Physical Review Special Topics journals, it is available for free.

If you're feeling brave, try answering some of the questions in the sample exam they have at the end of the article. Just reading them gave me those heart palpitaions that all my college finals used to inspire.

Read the rest of the post . . .

Sunday, October 15, 2006

Wave/Particle Duality Living Large

Wave/particle duality is usually a quantum phenomenon confined to photons, electrons, protons, and other ultra-tiny objects.

Quantum mechanics shows that such objects sometimes behave like particles, sometimes behave like waves, and sometimes like a little of both. All objects exhibit wave/particle duality to some extent, but the larger the object the harder it is to observe. Even individual molecules are often too large to show the quantum mechanical behavior.

Now physicists at the Université de Paris have demonstrated a classical version of wave/particle duality with a droplet made of trillions of molecules.

The experiment involved an oil droplet bouncing on the surface of layer of oil that was vibrated vertically. (Check out some pretty pictures of a bouncing oil droplet from a previous, related experiment by the same researchers in a press release put out by the French National Center for Experimental Science last year.) The droplet created waves on the surface, which in turn affected the motion of the droplet. As a result, the droplet and waves formed a single entity that consisted of a hybrid of wave-like and particle-like characteristics.

When the wave/droplet bounced its way through a slit, the waves allowed it to interfere with its own motion, much as a single photon can interfere with itself via quantum mechanics. Although the wave/droplet is clearly a denizen of the classical world, the experiment provides a clever analog of quantum weirdness at a scale that is much easier to study and visualize than is typical of many true quantum experiments.

A paper describing the research, Single-Particle Diffraction and Interference at a Macroscopic Scale, was published in the October 13, 2006 issue of Physical Review Letters.

Read the rest of the post . . .

Friday, October 13, 2006

Controversy-Plagued Element 118, the Heaviest Atom Yet, Finally Discovered

Element 118 has been created in experiments conducted at the Flerov Laboratory of Nuclear Reactions in Dubna, Russia by a collaboration of researchers from Russia's Joint Institute for Nuclear Research and the Lawrence Livermore National Laboratory in California.

Element 118, the heaviest element yet found, was produced through collisions that fused together Californium and Calcium atoms. Although element 118 is too unstable to detect directly, the presence of daughter elements resulting from the decay of element 118 gave clues to its fleeting existence.

Researchers at the Lawrence Berkeley National Laboratory previously reported the synthesis of element 118 in 1999, and later retracted their results when subsequent experiments failed to confirm their discovery. It was alleged that researcher Victor Ninov fabricated the experimental data that indicated the formation of element 118 atoms.

The (re)discovery was reported in the American Physical Society journal Physical Review C on October 9, 2006.

Read the rest of the post . . .

Thursday, October 12, 2006

Interesting reads for the day...

Water Pistol of the Sea I'm not much into fish, but how can you not love one that shoots water at prey up to 1-m above its head and then catches it as it falls? The movie is SO COOL! (You can find another movie here that is not as cool, but is set to music!)

Fixed Earth Yep, you read it right - fixed earth. This self-proclaimed "non-moving Earth & anti-evolution web page of The Fair Education Foundation, Inc." site explains that the earth doesn't revolve around the sun or rotate...and it explains how a fixed earth disproves evolution...

*I don't advertise this site to promote it nor to make fun of it, but I think every science enthusiast should be aware that people with these beliefs are still around.

Rising ACT Scores The national scores are on the rise...this article talks a little about what that means. I found the 2006 ACT scores by state to be interesting - though be careful in comparing state to state because they're not normalized by the % of students that took the test (in the sense that some states require all students to take it and others don't). But seriously, what is with DC? Anyone know if SAT scores also increased?

Read the rest of the post . . .

Reverse Fluorescence May Enhance Solar Cells

Fluorescence is what gives some pigments an oddly bright, vivid appearance. In fact, fluorescenct pinks, yellows, greens and other colors seem too bright because they really are brighter than they should be. That is, they have molecules that steal light from one color and add it to another. Fluorescent yellow pigment, for example, both reflects yellow light and converts other colors of light hitting it, changing them to yellow as well.

Typically, a fluorescent material converts light to colors lower down the spectrum. High energy blue light, for example, may be converted to lower energy green. Now researchers have developed chemicals that can go the other way, converting lower energy green light to blue.

The advance could lead to improved solar cells by converting unusable light to colors in a cell's useful range.

This isn't the first example of reverse, or up-conversion, fluorescence, but previous experiments only worked with coherent laser light. The new technique converts incoherent light, which is what the sun produces.

One small caveate - it's not very efficient yet. The method converts about 1% of green light to blue. Also, the researchers point out that it will be much more useful to find materials that will convert even lower energy infrared light to something solar cells could handle.

I'm hoping it will eventually lead to an ultra-modern version of those black light posters they used to sell in the mall. Only now, instead of an ultraviolet black light, maybe you could have a special, party-edition space heater to put out infrared light and make your Elvis poster glow.

To learn more about the up-conversion fluorescence experiment, visit APS Focus which covers the paper that appeared in Physical Review Letters on October 6.

Read the rest of the post . . .

Wednesday, October 11, 2006

Don't Amp Up to Fight Noisy Classrooms

Schools all over the nation are considering adding sound amplification systems like this one to help students hear better. Poor hearing can lead to poor student performance.

But scientists at the Acoustical Society of America, which has been studying the problem of classroom noise for 50 years, ask: wouldn't it be better to have a quieter classroom so students and the teacher could hear each other more naturally?

Noise from amplification systems can penetrate into classrooms next door. Then that classroom would need amplification, then the one next to it, and the one next to it, and so on. Also, having a central amplification system might mean that children would have to step up to a microphone to speak to the teacher. This might cut down on whispering during class, but it would also discourage the shyer students from stepping up to the mike and asking their questions.

The ASA recommends a national standard for classrooms installing damping systems to cut down on noise from other classrooms, or planting trees outside a noisy streetside window, or other solutions that don’t involve creating noise to fight noise.

Read the rest of the post . . .

Matter/AntiMatter Molecule Created

Scientists at CERN, a giant particle accelerator straddling the border between France and Switzerland, have created the first molecule made of both matter and antimattter.

The researchers made the molecules by slowing antiprotons and letting them interact with hydrogen molecules, leading to molecules consisting of a single proton bound to a single antiproton, as well as leftover hydrogen atoms.

(Bear in mind that scientists have long ago managed to join electrons and positrons together into positronium, which is a lot like a molecule, but molecules really should have atoms in them, rather than just electrons and their antimatter positron partners.)

The researchers reported their work in this week's edition of Physical Review Letters.

Now the big question -- what do we call the stuff?

The CERN folks are going with "antiprotonic hydrogen." A bit hard on the tongue, I think.

My friends at Physics News Update (PNU), who reported the story first, like "protonium." That's probably the best bet, but if we are following convention established with positronium (which is named after the antimatter particle), it should be called "antiprotonium."

Wikipedia already has an entry for protonium, so I think my PNU friends have made the right call.

Regarding the graphic above, you can't really take pictures of atoms and small molecules, but these shapes (spherical harmonics) are closer to the way hydrogen atoms would actually look if you could see them. If CERN releases images of protonium/antiprotonium/anitprotonic hydrogen, I'll post those instead.

Read the rest of the post . . .

Tuesday, October 10, 2006

Eggcentric Universe

The universe might be egg-shaped, according to stories in USA Today, the LA Times, and the People's Daily in China, among other publications.

It's a cute story, though a tad overblown in a couple of ways.

First of all, although it's based on research published in Physical Review Letters, the authors themselves are more cautious about their conclusions than you might guess from the coverage.

It's true that if they are right it will be the simplest way to explain one mysterious feature in the measurement of the cosmic microwave background. On the other hand -- interpreting the data with the simple explanation that the universe is not perfectly spherical will lead to a question that might be much harder to answer - specifically "Why the heck would it be anything other than spherical?" I'm guessing that most cosmologists are going to look into the other alternatives before they turn to the egg-shaped universe possibility.

The news stories are also eggzagerating the egg-shape, or eccentricity, a little bit. One percent eccentricity is hardly egg-shaped. I doubt you could tell if your bowling ball were out of round if it was only 1% eccentric.

Here's an applet that lets you fiddle with the eccentricity of an ellipse to help you get a feel for the affect on shape - the more eccentric it is the more egg shaped it is. It doesn't look very egg-like to me until the eccentricity reaches about 60% (0.60) at least. At 1% (0.01), which is the eccentricity that the researchers proposed for the universe, it looks essentially round.

Read the rest of the post . . .

Stop faking it!

I recently registered for a teacher workshop called "Force and Motion: Stop Faking It!" Turns out the National Science Teachers Association has a whole line of Stop Faking It materials for teachers. Although it was mildly demeaning to register for the workshop, like buying a "...for Dummies" book, I'm interested to see how it goes.

There has been a lot of emphasis in physics education research on identifying students misconceptions of physical concepts, but in my opinion, far too little teacher-friendly resources for overcoming them - especially at the middle and high school level. The best book I've found is Targeting Students' Science Misconceptions by Joseph Stepans.

Regardless, I think NSTA has hit on a great theme. I'm hopeful that they'll soon offer "Adulthood: Stop Faking It!" and "Work: Stop Faking It!" workshops.

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Monday, October 09, 2006

String Theory, Loop Quantum Gravity, and the Crackpot Index

Years ago, John Baez compiled the Crackpot Index to give the misguided visionaries among us some idea of just how crazy we are. Any positive score is bad, but if you're pounding the pavement trying to promote a new theory, you should take the test. The index includes thirty seven criteria, each worth from -5 to 50 points. The higher your score the more you should consider seeking professional help.

Just for kicks, I thought I would see what sorts of scores String Theory and Loop Quantum Gravity would get. Bear in mind that I don't know enough about either one of these theories to have my own opinion. I'm only evaluating them based on how they look to a naive outsider like me (and a lot of regular folks watching from the sidelines).

Here's John's abreviated Crackpot Index with a running total for String Theory (ST) and Loop Quantum Gravity (LQG). . .

In the interest of saving space, I only include the criteria that earn points for one theory or the other. Visit John Baez's full Crackpot Index page if you're wondering what I left out.

1. A -5 point starting credit.

Thanks John. I think we'll need them.
ST=-5, LQG=-5

3. 2 points for every statement that is clearly vacuous.

This is a tough one. Some folks on either side might make the claim against multiple parts of the opposing theory. So, let's be gentle and go with 2 points each.
ST=-3, LQG=-3

11. 10 points for beginning the description of your theory by saying how long you have been working on it.

I'm going to give this to ST. I can't tell you how many times I've heard the story about that guy toiling away in his attic in the 1970's and coming up with the rudiments of ST.
ST=7, LQG=-3

12. 10 points for mailing your theory to someone you don't know personally and asking them not to tell anyone else about it, for fear that your ideas will be stolen.

Man, these people sure don't have a problem with this one. Take a few minutes to peruse the archives and you'll see what I mean.
ST=7, LQG=-3

13. 10 points for offering prize money to anyone who proves and/or finds any flaws in your theory.

Three words: Physics Nobel Prize
ST=17, LQG=7

14. 10 points for each new term you invent and use without properly defining it.

M-THEORY!!!! ST wins this one, hands down.
ST=27, LQG=7

15. 10 points for each statement along the lines of "I'm not good at math, but my theory is conceptually right, so all I need is for someone to express it in terms of equations".

Quite the opposite is true. These people are GREAT at math. But, I'm still giving out some points. They are more likely to say "I'm not good in the lab, but my theory is conceptually right, so all I need is for someone to prove it with a really clever measurement." On the positive side, ST theorists sometimes suggest that there may NEVER be a way to test their theory, so they only get half credit
ST=32, LQG=17

17. 10 points for arguing that while a current well-established theory predicts phenomena correctly, it doesn't explain "why" they occur, or fails to provide a "mechanism".

Congratulations! Both win here. I mean, quantum mechanics works, and general relativity works, but the intersection of the two is a mess that both ST and LQG are intended to solve.
ST=42, LQG=27

18. 10 points for each favorable comparison of yourself to Einstein, or claim that special or general relativity are fundamentally misguided (without good evidence).

Have you seen the opening scenes in Brian Greene's "The Elegant Universe," NOVA production with the shot of Einstein's hand falling from his equation covered notebook? ST gets the points.
ST=52, LQG=27

19. 10 points for claiming that your work is on the cutting edge of a "paradigm shift".

Woohoo! Another winner for both.
ST=62, LQG=37

21. 20 points for suggesting that you deserve a Nobel prize.

OK, I've never actually heard anyone on either side make the claim out loud. But come on, in your hearts you know it's true.
ST=82, LQG=57

23. 20 points for every use of science fiction works or myths as if they were fact.

Parallel universes. Twenty points each. 'Nuff said.
ST=102, LQG=77

25. 20 points for naming something after yourself. (E.g., talking about the "The Evans Field Equation" when your name happens to be Evans.)

I'm not absolutely sure that I have this straight, but the rumor is that Ed Witten (one of the smartest people around, btw) chose the name M-theory by taking his last initial and inverting it. That's good enough for me. Twenty points for ST.
ST=122, LQG=77

26. 20 points for talking about how great your theory is, but never actually explaining it.

I'm gonna give ST full credit and LQG half credit for this one. It's your own fault, ST folks. Ya'll keep saying how pretty your theory is, then backing it up with donut/coffee cup stories that are not really that interesting.
ST=142, LQG=97

29. 30 points for suggesting that a famous figure secretly disbelieved in a theory which he or she publicly supported. (E.g., that Feynman was a closet opponent of special relativity, as deduced by reading between the lines in his freshman physics textbooks.)

I should give this one to everyone in the world who repeats Einstein's quote about god and dice. Since the rest us aren't playing, ST and LQG get the points all to themselves.
ST=172, LQG=127

30. 30 points for suggesting that Einstein, in his later years, was groping his way towards the ideas you now advocate.

Both camps use this one from time to time. Thirty points each.
ST=202, LQG=157

33. 40 points for comparing those who argue against your ideas to Nazis, stormtroopers, or brownshirts.

Half credit each. Read the reviews of the books by Smolin and Woit - and the reactions to those reviews - to see what I mean.
ST=222, LQG=177

34. 40 points for claiming that the "scientific establishment" is engaged in a "conspiracy" to prevent your work from gaining its well-deserved fame, or suchlike.

ST has the high ground for the moment, as far as funding and publicity go. So the LQG people are left to scream "conspiracy." Forty points for LQG.
ST=222, LQG=217

37. 50 points for claiming you have a revolutionary theory but giving no concrete testable predictions.

Both theories win big here. Fifty points each.

And the Final Tally is ST=272, LQG=267

It's close, but String Theory edges out Loop Quantum Gravity by 5 points. I'd call that a tie. Everyone's a winner today!

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Somebody Set Up Us the Bomb - Must Have Been North Korea

AYBABTU, baby!

Even if you don't get the nerdy reference in the title or the line above, you probably have heard that North Korea claims to have detonated a nuclear weapon. I'm inclined to believe it, despite the fact that the estimates of the total yield of Kim Jong-Il's bomb are all over the map. In a single CNN article, China says they have detected a half kiloton yield, while Russia says that it was as large as 15 kilotons.

As I understand it, nuclear weapons with yields under a kiloton are very hard to detect, and pretty hard to build. It's actually easier to make a 20 kiloton weapon than a tiny one.

Considering the modest size and the short time it has taken North Korea to go from threating to build it to actually testing, it's clear that they must have built a fairly primitive atomic bomb rather than a hydrogen bomb, which is much harder to assemble in part because it needs a plain old atomic bomb to set it off. See the differences between the two nuclear weapon types here.

If you are both patient and determined to learn everything about nuclear test monitoring, check out the book Technical Issues Related to the Comprehensive Nuclear Test Ban Treaty by the Committee on International Security and Arms Control. It's free to read online, but a bit dense.

A more readable summary of nuclear test monitoring issues is available through Geotimes which is published by the American Geological Institute.

For the most part, monitoring nuclear tests is the domain of seismologists. CNN published this seismograph data from the North Korean test.

Read the rest of the post . . .

Saturday, October 07, 2006

Freak Waves

Q: When does three plus three equal ten?

A: When waves meet up in experiments to simulate monstrous freak waves that snap ships in half or topple oil drilling rigs.

Freak waves are rare, but satellite images and sailors' reports of waves in the open ocean rising up to tower over the surrounding surf show that they can reach the height of a twelve story building. They've caused numerous shipping disasters over the centuries, even appearing in epics of ancient mariners.

Until recently freak waves have defied physicists in search of an explanation of how they form. A study by Miguel Onorato of the University of Torino in Italy suggests we are closing in on an answer. It turns out that waves don't always obey simple math. When two waves combine, their total height is usually just the sum of the individual wave heights. When they start to get large and approach each other at just the right angle, however, they add up to more than the sum of their parts. In physics jargon, they combine nonlinearly.

Read more about it in Physical Review Focus.

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Friday, October 06, 2006

don't make eye contact - a way of the past?

Remember the nervous feeling in the pit of your stomach when you knew the teacher was about to call on someone to answer a question that you didn't know the answer too??? You know the drill - don't make eye contact, look thoughtful but not too thoughtful...I have some vivid memories of those feelings from my days at Wauconda High School.

Now some teachers are considering using handheld computers that randomly select the names of students to be called on. A U of Florida study showed that this was effective in increasing student participation and preparation for class. The technique was studied in high school math classes and was initially created as a response to the fact that some teachers tend to call on boys more often than girls. Read the University of Florida News story here.

Time will tell whether schools feel this is a worthwhile investment, but I'm glad it wasn't around when I was in school!

Read the rest of the post . . .

2006 Physics Ig Nobel: How Spaghetti Breaks

Basile Audoly and Sebastien Neukirch of the Université Pierre et Marie Curie won the 2006 Ig Nobel for their analysis that explains why spaghetti breaks into several pieces when it is bent.

Congratulations guys!

I should also offer my appologies,Basile and Sebastien, in case you fellas aren't too happy about this one (personally, I would consider it a kind of honor). You see, I first publicised the paper in a news tip sheet that I write for the APS. It appeared in Tip Sheet #50, which I sent out July 21, 2005.

Of course, they made the trip all the way from France to attend the ceremony at Harvard, so they can't be very upset. I guess I'll know when I can finally get through to see the video posted on the Ig Nobel site, but it seems to be swamped at the moment.

What the heck, it's an interesting story and the physics has real world applications (for predicting structural failure in bridges, buildings, and even human bones). Check out the extensive article about it in Science News, if you don't believe me.

I've also written an official APS press release about it, with a quote from SpaceKendra.

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Shine on

Be sure to look up when you go outside tonight! Tonight’s full moon is called the Harvest Moon because its bright light arriving just after sunset enabled farmers to work late into the night when harvesting their crops.

The Harvest Moon is the full moon that happens near the first day of fall (Sept 23).

During the fall the day-to-day time lapse in the rising of the moon changes dramatically for those in the far northern or southern latitudes. For those of us in the northern latitudes the time goes down from (on average) 50 minutes to 30 minutes. Great news for the farmers of old – since the harvest moon rises just after sunset and since the time lapse is extra short, they got a set of bright evenings to work through. Lucky them.

You can read more about what to look for in the sky tonight in the NSAS story Strange Moonlight . Or, if you don’t already have plans for tonight, check out a harvest moon festival near you and eat a mooncake .

For now, I leave you with this tune...

Shine On Harvest Moon (By Nora Bayes and Jack Norworth – 1903)
Shine on, shine on harvest moon
Up in the sky,
I ain't had no lovin'
Since January, February, June or July
Snow time ain't no time to stay
Outdoors and spoon,
So shine on, shine on harvest moon,
For me and my gal.

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Thursday, October 05, 2006

Chaos Turtle

My Mom's a physics nerd too. Here is a turtle she painted for the University of Maryland Fear the Turtle Sculpture Project.

It is covered in patterns derived from the research performed by the University's Chaos Group. Check out their chaos image gallery to see the sources of her inspiration.

The group has posted a Java applet that let's you zoom in on a fractal pattern so that you can get a feel for self similar patterns that are often associated with chaos.

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Wednesday, October 04, 2006

Einstein@Home Art Computer

How nerdy am I? I'll give you a hint - I do physics in my sleep. Specifically, I built a custom computer that runs the distributed computing project Einstein@Home 24 hours a day. You can see the project's ultra cool screensaver running in this photo.

The computer hangs on the wall behind my desk. I like to think of it as a kind of art installation. I call it "AMD Outside."

Here's a picture of it in the dark.

It has the following stylish bits: an AMD Athlon 64-bit 3700+ processor, a dedicated Linux drive, a dedicated Windows Drive, a shared Linux/Windows drive, a DVD-RW drive with the cover taken off so you can see the DVD spin (my son did that while I was at work), a persistence of vision display on the CPU cooling fan that constantly shows the temperature, a dual core processor capable mother board so I'll be able to upgrade when I have the cash, a power supply with a transparent cover so you can see the power transistors and monster sized capacitors, 1 Gigabyte of RAM with integrated LEDs that show how hard it's working on Einstein@Home, a TV card, a web cam so that I can check in on Shiner (my Australian Shepherd who suffers from epilepsy) while I'm at work, fluorescent cabling and custom phosphorescent paint along with 2 black lights to make it all glow in the dark, and a flexible neon light to decorate the otherwise boring drives.

I built this with the pieces left over after I fried my previous CPU by overclocking it WAY too much to get extra credits on Einstein@Home.

One advantage is that it is frees up valuable floor space in my tiny town house. It is also quiet - I used to run the overclocked machine in a case with seven fans in addition to the CPU fan and the two power supply fans. It sounded like a Cessna landing in the living room. Now it's almost totally silent and cooled by natural convection in the room.

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Wikipedia Physics

Wikipedia, the online encyclopedia that anyone can edit, is my favorite research tool. It's democratic (bordering on socialist), bigger and much more up to date than any print encyclopedia, and more reliably accurate than simply Googling something. Research in recent years, in fact, has shown that it's just as accurate as the Encylopedia Britannica, at least for science topics.

Despite all that, Wikipedia is not as good as it could be. A study published in the APS journal Physical Review E last month found that Wikipedia has similar structure to the World Wide Web and social networks like the network of human sexual contacts and the citation links between academic papers. That means that instead of broad, democratic topic selections being added to the wiki, most new articles are connected to older topics.

Network experts call this the "rich get richer" model.

As the wiki grows, we are going to get more and more information tied to what we already know. The researchers who did the analysis don't have a good explanation for it, but they point out that Wikipedia would be a better resource if we could find a way to get people to try start new topics instead of fleshing out what's currently posted.

I'm not so sure there is anything we can do to change human nature. Besides, Wikipedia is already so useful that I wouldn't dream of changing it. When I happen to find a problem, like something missing or innaccurate, I fix it. You should too.

In case you're wondering, the diagram here depicts the researchers' concept of how Wikipedia topics work. SCC stand for strongly connected concepts. The IN region indicates topics that connect directly to the SCC, the OUT region represents topics the SCC connect to and the worm-like tendrils are topics connected to the IN and OUT topics, but not to the SCC. The tendril connecting IN and OUT represents links between topics that are part of IN and OUT but not tied to the SCC.

Simple, isn't it? (maybe not)

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Hubble Finds 16 New Planets

Check out the NASA press release about the 16 new planets that Hubble found.

Or read the more concise Wikinews story by my friend mputney.
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Tuesday, October 03, 2006

Microwave Map of the Universe Wins 2006 Physics Nobel

I came to work early today to catch the Nobel Prize in Physics announcement.

It went to John Mather and George Smoot for their work on the Cosmic Background Explorer (COBE), which provided a map of the universe just after the Big Bang.

You can read more in the Wikinews entry I posted this morning.

This one comes as no surprise to Nobel Prize watchers. COBE researchers have been short list favorites for years now.

In case anyone noticed my 2006 Nobel prediction . . . I was wrong. But so were those Science Citation folks at Thomson Scientific publishing.

My friend Davide Castelvecchi, however made the right call last week! I have the email to prove it. Good job, Davide!

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Monday, October 02, 2006

Trouble at the alma mater

I'm coming into this story a little late, (I'm catching up on my reading after being out of commission for over a month) but this story hit me especially hard as it takes place in a graduate dept just a few buildings from where I got my MS.

Everyone knows that science graduate students have it hard, but imagine the added pressure that comes with knowing your advisor is falsifying data.

Last winter six graduate students in a biology program at UW-Madison turned in their advisor for concerns about data falsification (eventually found to be true). As a result their advisor resigned, the lab shut down, and 5 of the students were told that much of their previous work was not useable and that they'd have to start over with new projects if they still wanted Ph.D.s.

From a recent article in Science:
"...the graduate students caught in the middle have found that for all the talk about honesty's place in science, little good has come to them. Three of the students, who had invested a combined 16 years in obtaining their Ph.D.s, have quit school. Two others are starting over, one moving to a lab at the University of Colorado, extending the amount of time it will take them to get their doctorates by years. The five graduate students who spoke with Science also described discouraging encounters with other faculty members, whom they say sided with Goodwin [the advisor] before all the facts became available."

Yikes...I raise my glass to those students. And hope I'd be courageous enough to do what they did.

To read more:

Science Magazine (subscription required)
Wisconsin State Journal
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Squeezing Song from Sand

You can't squeeze blood from a stone, but you can get sound out of sand dunes. Singing dunes often make sound on their own, as a result of spontaneously coordinated avalanches of sand, according to a paper recently featured in Physics News Update.

What I hadn't realized is that people can effectively play the dunes by pushing sand to create their own avalanches. The researchers who studied the sounds of the dunes collected some videos of people scooting down dunes to make tones, and posted the clips on their (poorly designed) web page. They also built the apparatus shown above to make their own sand sounds.
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