Thursday, December 07, 2006

Our Phavorite Physics Stories of 2006

It's the end of the year, so it's time to reflect on the past twelve months. In case you’re already saturated with 2006 retrospectives, we’ll keep ours brief. These are all our own humble opinions of the special stories, of course.

The Most Scientifically Important Physics story of 2006 . . . NASA's discovery of hard evidence for dark matter.

Runner up to the Most Scientifically Important Physics story of 2006 . . . The (Re)Discovery of Elements 116 and 118.

The Most Fun Physics story of 2006. . .
The Ig Nobel Award for a study of why spaghetti breaks in more than two pieces when it is bent.

Runner up to the Most Fun Physics story of 2006 . . . Bad Basketballs

The Most Over Blown physics story . . . A cloaking device that got the press excited, but will probably never work on anything larger than a dust speck (which is pretty hard to see already).

Runner up to the Most Over Blown physics story . . .
The Eggcentric Universe. (It’s one explanation for measurements of the cosmic microwave background, but nearly nobody thinks it’s the right one.)

Invention Most Likely to Lead to a new Comic Book Superhero (or Supervillian). . . Radioactive scorpion venom for brain cancer therapy.

Invention most likely to become a Comic Book Supervillian Weapon . . .
The Paser

Most Controversial Experiment . . . Sonofusion Bubbles Up and back down.

Worst Physics Miscalculation . . .
Germany to win 2006 World’s Cup of Football. Italy actually took the cup.

Worst Pending Physics Miscalculation . . . Physicists Predict Stock Market Crashes

Biggest Physics Cat Fight of the year . . . String Theorists vs. Loop Quantum Gravity Theorists

Let us know if you have any suggestions for the year's most notable physics stories (even if you have to make up your own categories, like we did). I'll be happy to add it to the list, if you make a good argument. And if you really hate one of our choices, let me know why I should take it down
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Tuesday, December 05, 2006

How to tell if santa is real

As I was driving today the radio host I was listening to was talking about the results of a mall-santa survey that included questions like "how many of you have been peed on by a child?" (unfortunately that won't be the subject of this post), "how many of the children say they've been good?" etc. The question that caught my attention was this:

Q: How many of you have your beard pulled on at least once a day?
A: 90%

Why do I find this interesting? The radio hosts were talking about how kids pull santa's beard to see if their santa - in the middle of nowhere Illinois or in downtown New York City - is real.

It got me thinking about how people test whether something is real, which we have to do all the time in physics and in life. The tools we use to make these judgments develop and change over a person's life, at least they have over mine, but it's interesting to take a moment and think about what your tools are and where they've come from.

In my (personal and teaching) experience intro physics students start out kinda like babies in that they often believe things because of the "NASA effect." In other words, "I know the moon is bigger than the earth because NASA says so" or more commonly "...because the book says so." Just as many of us believed in santa because our parents told us he was real.

As I got older I started testing things myself (how hot the stove was, what happened if I didn't clean my room, what I really thought about religion, etc.), but even the methods I use to test things has changed...when I was 5 yrs old I decided whether santa was real by pulling on his beard. If I had to decide now I'd probably carry out some additional tests...check his drivers license, ask to meet his wife, give him a punch in the stomach (not to be mean, to check for a pillow), dna tests, etc. Of course I don't have to decide now; I make that decision a long time ago when I pulled on santa's beard.

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Thursday, November 30, 2006

Adopting Physicists and Mac & Cheese

Why did you become a physicist?

Do you enjoy mac and cheese?

How does particle physics contribute to future advances in the United States and the world as a whole?

Are you an outdoorsman?

Ever want to ask a physicist one of those questions? One of the projects I'm working on for the American Physical Society is called Adopt-a-Physicist and I thought I'd tell you a little about it today because it's just that cool! Don't worry, I'm not soliciting anything - it's a totally free project that is already underway.

This program is designed to show high school students what it's like to be a REAL physicist - by giving them a chance to interact with physicists one-on-one via online discussion forums. Participating physicists include researchers at all kinds of labs and companies, computer programmers, doctors, science writers, and many others.

Classes that participate in this program "adopt" up to three physicists (a physicist is defined as anyone with a bachelor's degree or higher in physics). Each physicist hosts a forum where he or she interacts with the students and answers any questions they have about life, careers, their field of study, etc. Hopefully they will help students realize that you don't have to have bushy white hair to be a physicist.

And the coolest thing? Anyone can read their discussion!

To browse the forums:

1. Go to the comPADRE registration form* (Digital Resources for Physics and Astronomy - don't ask me how that makes up the acronym comPADRE...) and create a login
*it's free and easy and you don't get spam

2. Go to the Adopt-a-Physicist website

3. Click on the "Log in" option at the top of the homepage (the regular login, not "student login")
and log in with your new comPADRE login

4. Click on the "Forums" option at the top of the page and choose the "Fall 2006 Physicists" forum list

5. Click on any physicist's name to view his or her discussion forum
-The most current threads in each forum are at the top, so you might start by scrolling down to the bottom when you open a new forum
-You can view a physicist's profile by clicking on his or her name once you are in the forum

PS - Gary White does enjoy mac & cheese

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Tuesday, November 28, 2006

Erasing the Day?

Sorry it's been a week since we last posted. That doesn't mean there haven't been any good physics stories or deep thoughts on physics - since we all know physicists work even on their days off - it just means we've been busy with turkey and family and Hawaii (yeah, I wish that was me).

The Palo Alto Research Center Incorporated and Xerox Research Center of Canada are working together to create erasable paper - paper that be reused many times, according to a New York Times story. Apparently office workers today use paper mainly for daily tasks, such as making notes or printing emails for quick reference, and rely on computers for long term storage.

I know that I'm constantly throwing away or recycling post-its and notebooks full of random notes that have contributed to a finished product safely stored (I hope) on a network drive. So, says Xerox, why not make paper whose ink fades in 16 hours? Then you can reuse it over and over. Not a bad idea, as long as you don't accidentally print your boarding pass on said piece of paper 17 hours before you have to board the plane. That would be bad.

The article doesn't go into much detail about the process, with the explanation consisting of "[the paper is] based on compounds that can change color when they absorb a certain wavelength of light, but can then gradually revert to their original." I need a little more than that to go on. It kind of reminds me of the secret codes we wrote when I was younger - dip a toothpick in lemon juice, write a "secret message" and hold the paper up to a lamp or under an iron to read it.

Of course the big question in all of this is - will there be a market for such technology? It is supposed to be cost-effective (Xerox plans to make the paper available for 2-3x the cost of regular non-reusable paper), but as people turn more and more to electronics to write and store their information, who knows if there will be a visible payoff for this research...

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Tuesday, November 21, 2006

Giving thanks for science

Listen to the text-to-speech Robo-Podcast.

With the thanksgiving holiday approaching, many of us will soon sit down to worship our food (note the Over the Hedge reference) with family or friends. Whether you eat turkey or have one of the non-traditional main dishes, be sure to take a moment to appreciate the science your feast represents and give thanks for the many advances in science that have led to the 20 lbs turkey and the ability to store leftover potatoes and gravy throughout the week it takes to consume them.

My favorite food at thanksgiving dinner is the heap of turkey, gravy, potatoes, and stuffing all mixed together that makes up my first course. I used to prefer apple pie over pumpkin, but pumpkin has really grown on me in my old age. Yum, I'm getting hungry thinking about it.

Anyway, imagine preparing thanksgiving dinner for all the relatives over a fire instead of a state-of-the-art Maytag or GE. Or making your pie with real pumpkins instead of the gooey mix from the local grocery store. Or even using green beans and corn straight from the garden – which you’d need to do without the modern ability to preserve them and have them available any time of year.

Thanksgiving would certainly be possible without all the modern conveniences, but it would take a lot more time to create feasts as extravagant as many of us will enjoy on Thursday. So this holiday as you think about how lucky we are to live in a free country and send a nod of thanks to the pilgrims and founding fathers, take a moment to appreciate the science that makes this day of food and football a little bit easier, and that enabled your aunt to walk again after breaking her hip, your grandpa to recover from cancer, your to sister fold laundry downstairs while listening for her baby's cry though the monitor, you to keep in touch with long distance friends, and your loved ones to come home for the holiday. And then have another piece of pumpkin pie.

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Friday, November 17, 2006

Terraced Droplets

Liquid droplets are usually rounded, as I am sure you know. But when the droplets are made of certain types of long molecules, they turn into terraced pyramids instead.

The molecules in this drop have different structures on either of their ends. The end of one molecule is attracted to only one end of a neighbor molecule, and repelled by the other. The molecules behave a little like magnets, except that it's a chemical attraction that lines them up instead of magnetic fields.

Because of the interaction between the molecules' ends, they form drops built of layers - leading to these pretty physics pictures.

The molecules in a single layer are lined up with each other, but are lined up in the opposite direction of the molecules in the layer immediately above or below.

If there is only enough material in the droplet to for a single layer, it turns into a pancake like the picture below.

I'm not sure what makes the rays that extend out all around, but it sure is cool.

In case you're wondering why you've never seen terraced drops, it's because it only happens for long molecules in very tiny drops. The drops in these images are ten or twenty millionths of a meter across. The researchers took the pictures with a high resolution atomic force microscope.

The images come from an article by Andrew B. Croll, Michael V. Massa, Mark W. Matsen, and Kari Dalnoki-Veress of McMasters University in Ontario and the University of Reading in the UK. It was published today in the journal Physical Review Letters.

Read the rest of the post . . .

Thursday, November 16, 2006

Wireless Power

Listen to the text-to-speech Robo-Podcast

You've got a cell phone, a wireless laptop and maybe a Blackberry. You are the very picture of a wirelessly connected person on the go - until your batteries run down.

Wouldn't it be great if you could recharge all your electronics without having to plug into a charger?

A group of physicists from MIT thinks so too. They're proposing a design for a wireless power transmission system that could make power cables and battery chargers things of the past. What's more, the researchers believe the power source could run buses or possibly even nano-robots tooling around inside your body.

Marin Soljacic and his MIT colleagues presented their idea at the Industrial Physics Forum meeting going on this week in San Francisco. It created quite a stir in the press, leading to stories in major newspapers and dozens of techy websites.

The system Soljacic is proposing doesn't broadcast power the way an antenna does. Radiating energy out to space would be wasteful. Instead, a power source creates a short range oscillating electric field. Properly tuned circuits that are within range of the source suck up some of the energy. If there are no electronics to charge or power nearby, then most of the unused energy returns to the source.

As an incurable early adopter, and electronics junky, I can't wait to get the system in my house. The only problem is, I don't think it will work.

Soljacic 's idea is based on old established science, well within the grasp of nineteenth century electronics wizards like Marconi, Edison and Tesla. There's no reason that the system, if it's feasible, couldn't have been built over a hundred years ago. Soljacic has suggested that it's an idea whose time has come only with the advent of wireless communications.

But I'm not buying it. I'm sure my great grandmother would have appreciated a cordless vacuum back in 1910.

So, despite the fact that I would give my eye-teeth for wireless power, I'm not going to hold my breath.

One problem is likely to be the inefficiency of wireless power. Even Soljacic 's calculations show that the best you could get is 60% efficiency. I'd bet Tesla and Edison gave it a shot and found that it's much worse in real world conditions. Of course it might make a nice combination power source and space heater, after all the wasted energy has to go somewhere. I'm guessing it goes into heating the room.

On the other hand Soljacic may be onto something. If I'm wrong, and his wireless power works, I'll be first in line at Walmart to pick one up.

Read the rest of the post . . .

Wednesday, November 15, 2006

Fabulous Fisics Fotos

Every year the American Association of Physics Teachers sponsors a physics photo contest for high school students. This year they partnered with Lexmark International, Inc. Here are some of my favorites...

Magnetic Distortions
I love this picture, taken by Bahoa Pan of Cranbrook Kingswood School and awarded honorable mention in the competition. The horseshoe magnet was placed on a CRT computer monitor to illustrate how a magnetic field deflects charges. Read Bahoa's description here.

Bending Water
Look closely - see the stream of water attracted to the balloon? This picture of a charged balloon attracting water molecules, taken by Matthew Claspill of Helias High School, was a second place winner. I've done this demonstration before with a charged comb and I admit that it's pretty neat, but this picture is awesome! I'm using a balloon next time.

Demonstration of Newton's 1st Law
Kevin Rosenquist of West Chicago Community High School took this first place picture. He filled a long balloon with water, set it on a railing, and punctured the balloon to demonstrate Newton's first law. The picture was taken after the balloon retracted but before the water spilled down the railing.

Coil of Smoke
This picture of a coil of smoke, also a first place winner, was taken by Marina Autina of Treasure Valley Math & Science Center. It's a beautiful picture taken to illustrate the laminar and turbulent flow of the smoke.

I've always been a fan of science and art and I think this program is a great way to let students explore science using technology and art. I'm not sure need to mention how important good communication is in science - but let me emphasize that pictures can be worth a thousand words - even in science. Sometimes more. A big congratulations to all of those that submitted pictures this year!

Read the rest of the post . . .

Tuesday, November 14, 2006

Twining Vines

Listen to the text-to-speech Robo-Podcast

Have you ever wondered how the vines in your yard manage to work their way up a pole or a tree? The question puzzled Darwin and remained a longstanding mystery - until it was solved in a paper published in Physical Review Letters earlier this month.

The answer is summarized in the latest edition of Physical Review Focus. I have to tell you though, I have a hard time following the article in my attempt to understand exactly how the model works.

There's one thing I understand from the Focus story - the theory can tell you the largest diameter stick you should use to hold up vines in your garden. Specifically, if you measure the diameter of the curls that a vine's tendril makes when it is not wrapped around a support, then you should make sure your supports are not more than 3.3 times larger than those curls in cross section. Otherwise, your twining peas will droop and your morning glories, will lie ungloriously on the ground.

Read the rest of the post . . .

Monday, November 13, 2006

Hot Nanotech

Toothpaste that automatically coats, protects, even rebuilds tooth enamel; nanoscopic electronics; and maybe, someday, tiny robots capable of performing minor surgical procedures within the human body . . .

These are just a few of the cool technologies that are the focus of the AIP Industrial Physics Forum meeting in San Francisco this week.

Check out Jennifer Ouellette's reporting on the meeting in the Physics Today blog.
Read the rest of the post . . .

Saturday, November 11, 2006

Cosmological Constant Conundrum

I was browsing the online archives of physics papers today when I stumbled across an intriguing paper by Abraham Loeb of Harvard.

Loeb claims that a search for planets in dwarf galaxies could test, and possibly debunk, a common explanation for the puzzling measurement of the cosmological constant, which drives the accelerating expansion of the universe.

Einstein initially proposed the cosmological constant, as a part of his theory of general relativity, to explain why the universe appeared to be static. When Edwin Hubble showed that the universe is actually expanding, Einstein dropped the constant from his theory, calling it the greatest blunder of his career.

It turned out later that Einstein might have been on the right track for the wrong reasons. The universe is not simply expanding, but accelerating as well. As a result, physicists resurrected the constant and found that it must have a value around 0.7 to match our observations of the universe.

Although it is a tidy explanation of the universe's accelerating expansion, the observed value is problematic. Some promising theories predict that the constant should be thousands of times larger than it seems to be, while others require it to be exactly zero. None seem to predict the value we actually measure (although string theory may offer a mechanism that allows the constant to decrease as the universe goes through many Big Bang and Big Crunch cycles).

One popular, though controversial, explanation for the measured value stems from the idea our universe is only one of many in an enormous multiverse, and that the cosmological constant may take on different values in different universes. According to the anthropic argument, most values of the constant lead to sterile, lifeless universes, while only values near the one we see are conducive to life. We measure a small cosmological constant because we wouldn't be around to measure a larger one, regardless of how unlikely a small constant is among the nearly countless possible universes. It's a pat argument and difficult to argue with, considering the fact that we can't visit other universes to check it.

Loeb, however, thinks we can do the next best thing right here in our universe by looking for planets in nearby dwarf galaxies. The conditions in dwarf galaxies, when they formed in the early universe, were apparently similar to those that would exist in universes with cosmological constants thousands of times higher than ours. If we find plentiful planets in dwarf galaxies, some of which are likely to be conducive to life, then Loeb says that we can be 99.9% confident that anthropic calculations of the cosmological constant are meaningless.

Loeb points out at the end of his paper that there might be an added benefit to finding planets in old dwarf galaxies "If the anthropic argument turns out to be wrong," he writes, "and intelligent civilizations are common in nearby dwarf galaxies, then the older more advanced civilizations among them might broadcast an explanation for why the cosmological constant has its observed value."

*Personal opinion warning*

I think Loeb's paper could have profound implications for theories that predict multiple universes with random cosmological constant values. (String theory, for instance, suggests that there are as many as 10^500 possible universes - that's a ten with 500 zeroes after it - with all sorts of values for the fundamental constants).

According to multiverse theories, our universe is already unusual because the other constants (such as those controlling the strength of gravity, electromagnetic interactions, etc.) are finely tuned to support life. If life can exist in universes with high cosmological constants, then we can't use the anthropic argument to explain ours. How much more unlikely must it be, then, for us to have an unusual value for the cosmological constant? (I would say N/10^500, where N is the number of habitable universes with cosmological constant of about 0.7. I have no idea what N should be, though.)

I may be making an illogical leap here, but if it turns out that we can't make a case for an anthropically determined value for the cosmological constant, then any theory that says our constant is unlikely is equally unlikely to be true.

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Thursday, November 09, 2006

Mercury Waves Hello

Yesterday (Nov. 8), people in the Americas, Hawaii, and around the Pacific Rim set up their telescopes (with solar filters of course) and watched Mercury pass directly in front of the sun. Cool! I didn't get to see the transit, but thanks to the internet there are all sorts of great pictures available today.

In this picture (taken by Howard Eskildsen in Florida) you can see a sunspot in the upper left and the nice round shape of Mercury on the lower left. has a gallery of images that is being updated all day.

Mercury passes between the earth and the sun about 13 times a century - if you missed it this time your next chance will be May 9, 2016. Mark your calendar now!

2003 Transit of Mercury

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Tuesday, November 07, 2006

Stop Faking It! II

Earlier this year I posted about registering for a Stop Faking It! workshop. Well, last week I attended the workshop as part of the National Science Teachers Association Area Conference in the lovely city of Baltimore - it was fabulous! Actually the whole conference was. I was impressed with the variety of sessions and the quality of nearly all of the sessions that I attended.

This workshop was led by the amusing and energetic author of the Stop Faking It! materials, Bill Robertson. Bill took the 40 of us K-12 educators through force and motion concepts using the learning cycle model. We had a great time playing with chairs, ping pong balls, and balloon rockets; but the real fun was the audible "ah-ha" moments when the science behind these (sometimes commonly used) activities sunk into our brains for the first time.

Most of the sessions at the meeting were aimed at helping teachers teach science concepts to students, but Bill's workshops (and books) focus on helping teachers better understand concepts. See, he believes that teachers with a deep understanding of the science behind textbook claims will be more effective, confident teachers.

I studied physics for a long time, but this 4 hour workshop exposed the sloppy thinking that I've fallen into and my tendency to look to equations to solve problems instead of concepts. What a great reminder of why physics is so cool!

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Sunday, November 05, 2006

I Vote for Science!

The 2006 US elections are just about here, and gizmo looks almost as stressed over it as I am. Maybe we should both cut back on the coffee for a bit.

"I vote for justice!" is the battle cry of SuffraJet, a rocket propelled, equal voting rights advocate and member of the Decency Squad, from the too-short-lived cartoon The Tick. I assume everyone who goes to the polls this Tuesday is voting for justice, at least their own interpretation of it. We could argue all day over how to vote for justice, so my battle cry is "I vote for science!"

I had hoped that the newly established, nonprofit Scientists and Engineers for America (geez, don't you hate those vague "up with goodness" organization titles that seem mandatory these days) could help me by compiling information about candidate positions on science issues. But as you can see for yourself, their page listing key races is blank. So I had to figure it out all on my own.

I'm nonpartisan and registered independent, but it's pretty clear this year when you look at important science issues that a vote for science is likely to be a vote for a Democrat. In Maryland, where I live, Michael Steele(Republican) is only in support of stem cell research that doesn't destroy an embryo, while Ben Cardin(Democrat) supports stem cell research in general.

OK, it's only one issue, and the positions of the candidates are nuanced enough that voting for science in this case is not so clear. But if you look at the record of the Republican congress and administration over the past six years, a vote for the GOP is a vote against rational science. The best way I see to change course is to change congress. Although I like Steele for lots of reasons, I'm voting against him to get his party out of power. I hope the Democrats can do a better job on science in the US.

In case you're wondering which issues matter the most to me, here's a partial list.

Space-based science: We are spending WAY too much money sending humans to space as part of the administration's agenda to put people on Mars. Robotic probes do a fine job exploring space for a hundreth the cost of risking humans. The International Space Station in particular is a waste of hundreds of billions of dollars with no sign of ever giving us interesting or valuable data. Let's cancel the trip to Mars and keep sending probes into space instead.

Stem cell research: I'm for it, with as few restrictions as possible. I'm an athiest, so I'm not distracted by questions of embryo souls and such superstition. When you rely on rational thought rather than primitive mythology, it's easy to support stem cell research.

Intelligent Design: The president expressed his support of teaching "both sides" of the debate over evolution. The fact is, there is hardly another side to the debate - there's the scientifically accepted theory of natural selection, and there's (barely) a handful of intelligent design supporters who are really out to teach religion in science class. I'm pretty sure someone just caught the president off guard with the question about teaching the alternatives. But the Republican party seems more inclined than the Democrats to support the psuedoscience of creationism and intelligent design.

Education: Rewarding the best performers and punishing the under-achievers is a great way to operate a free market, but an awful and irresponsible and short-sighted way to raise our children. No Child Left Behind leaves all sorts of kids behind, if they happen to live in lower tier school districts that will lose ground every year with this policy.

I am also concerned with our current energy, environmental conservation, higher education funding, and other policies that have gone awry in the past six years.

The bottom line - I'm voting for justice (i.e. science and Democrats) this year.

Read the rest of the post . . .

Thursday, November 02, 2006

For Once, Beryllium Outshines Diamond

Researchers from Sandia National Laboratories used the speed of sound to determine the shock melting pressure of diamond – and found it to be remarkably high. Not exactly the result researchers hoping to use diamond in inertial confinement fusion (ICF) fuel capsules were hoping to hear.

ICF is a technique that uses high-powered lasers to detonate the outer layer (called the ablator) of a small fuel capsule. This creates an inward-traveling shock wave that raises the temperature and pressure at the center of the capsule to fusion-igniting levels.

The ablator must be made of a material that can absorb the x-ray energy emitted in ICF but that also has a low atomic mass. Diamond and beryllium have been identified as prime candidates for use. Although diamond is attractive from a manufacturing and fabrication point of view, this research shows that it’s probably not the right choice for ICF applications.

The experiment showed that shock waves stronger than 10 million times atmospheric pressure are needed to completely melt diamond. Beryllium, however, needs less than 3 million times. In addition, diamond is a solid-liquid mix over a much larger range of pressures than beryllium is, placing further constraints on the design of ICF capsules made with diamond.

The researchers determined the pressure needed to melt diamond by hitting samples with aluminum/copper plates traveling at up to 54,000 mph. This created shock waves that caused a pressure wave to travel through the diamond at the speed of sound. The speed of sound is highly dependent on the phase of the diamond, so researchers were able to measure the pressures where melting started and was completed.

Recent advances in laser power and efficiency make ICF an attractive candidate for alternative energy sources. In addition, it has promising applications in defense and fundamental physics research.

You can read more about this research in the press release for the group's upcoming talk at the American Physical Society's Meeting of the Division of Plasma Physics.

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Wednesday, November 01, 2006

Physicists Reveal Fundamental Flaws in NBA's Synthetic Basketball

Synthetic NBA basketballs introduced this season — and despised by many players — are less lively, more slippery when damp, and bounce more erratically than the traditional leather balls, according to a preliminary study by University of Texas at Arlington physicists.

When Shaquille O’Neal, Kobe Bryant, Dirk Nowitzki and other superstar NBA players griped about the league’s new synthetic basketball, Mavericks owner Mark Cuban contacted James Horwitz, Chairman of the University of Texas at Arlington Department of Physics, to request a study of the properties of the new and old balls.

Horwitz responded setting up a UTA Physics investigative team, designating Professor Kaushik De as UTA Physics “MavBalls” project leader. According to the UTA physicists’ tests and preliminary results, the players’ complaints may be justified.

De, Horwitz, and their students have found:

* That the new balls bounce 5-8% less high than typical leather balls used in past seasons, when dropped from a little over four feet, requiring players to make adjustments to their shots and rebounds

* That the new balls are tackier when dry, which can improve grip, but are less absorbent. This causes the balls to become slippery when they get exposed to sweat or other moisture during a game. Such sudden changes in players’ ability to grip the ball could cause mistakes and turnovers during play. (Leather balls, on the other hand, become easier to grip when they become moist.)

* That the synthetic balls bounce 30% more erratically, leading to less predictable trajectory, which can cause problems during dribbling, rebounding and passing. The bounce is most erratic when the grooved surfaces on the ball, with the embossed Spaulding logo or NBA logos are involved.

Some of the ball’s shortcomings could potentially be corrected easily. Decreasing the depth of the ball’s embossing would reduce erratic bouncing. Over-inflating the ball to 14.5 psi, rather than the regulation 8.5 psi, is enough to get the synthetic ball to match the bounce height of a leather one. But improving grip on the synthetic compound will probably be a trickier problem. Keeping the ball dry with towels and frequently changing the game ball, as suggested by Cuban in his internet blog, Blog Maverick, may help reduce the slippery grip problem this season.

The study is a stark contrast to the assertions by Spalding, the ball’s manufacturer, that it is superior to leather basketballs. The UTA team however has not done any durability studies, which is one of the primary characteristics Spalding claims makes the synthetic ball better.

The UTA physicists point out that their current results are preliminary, and they are in the process of performing more extensive testing to definitively evaluate the controversial new basketball. Among other tests, they plan to subject the balls to aerodynamic tests in UTA's engineering department wind tunnel.

An executive summary of the study De, Horwitz and their students performed is posted on the UTA web site, as well as an article profiling the two physicists and their motivation for taking up the quest to evaluate the new NBA ball.

Read the rest of the post . . .

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.

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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.

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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

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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.

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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.

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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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