Archives for physics



Can Economic Growth Continue Forever? Of Course!

Tim Harford, who writes the Financial Times‘s  “Undercover Economist” column, has appeared on our blog many times. This guest post is part of a series adapted from his new book The Undercover Economist Strikes Back: How to Run or Ruin an Economy

Can economic growth continue forever? The internet seems to be full of physicists explaining that economists are clueless on this topic. There’s the late Albert Bartlett’s hugely popular videos – or Tom Murphy’s article “Exponential Economist Meets Finite Physicist.” The key issue is that exponential growth will eventually take you to impossible places. And by eventually, the physicists mean “sooner than we expect.”

Exponential growth is any kind of growth that compounds like interest payments. The classic example is the rice on the chessboard. According to an old story, the inventor of the game of chess was offered a reward by a delighted king. He requested a modest-sounding payment: one grain of rice on the first square of the chessboard, two on the second, four on the third, doubling each time. Yet this is actually a colossal amount—many times the annual rice production of the entire planet. Read More »



The Nobel Prize in Physics and Traffic Priority at Roundabouts

The 2013 Nobel Prize in Physics was recently awarded for symmetry breaking and its consequence, the Higgs boson—a particle so well known that, according to the president of the American Physical Society, “[i]f you’re a physicist, you can’t get in a taxi anywhere in the world without having the driver ask you about the Higgs particle.” Teaching the symmetry unit in my own course this semester, I couldn’t help wondering about symmetry as I drove through an apparent example of symmetry: roundabouts or traffic circles.

Roundabouts use two complementary systems for controlling traffic flow: (1) Traffic in the roundabout has priority, or (2) traffic entering the roundabout has priority. The choice seems so symmetric, like choosing right- or left-hand traffic. In the United Kingdom, traffic in the roundabout has priority. In contrast, on many Massachusetts roundabouts, including one on my commute, entering traffic has priority. Read More »



Faster Than Light: A Guest Post

I recently had occasion to e-chat with Rocky Kolb, a well-regarded astronomer and astrophysicist at the University of Chicago. Talk turned, of course, to the recent likely discovery of the Higgs boson — but, as Kolb talk about that, he raised an even broader and more interesting point about scientific discovery.

He was good enough to write up his thoughts in a guest blog post that I am pleased to present below:

 

Faster Than Light
By Rocky Kolb

After the news coverage of the past week, everyone now understands what a Higgs particle is, and why physicists were so excited about the July 4th announcement of its probable discovery at CERN, a huge European physics accelerator laboratory.  (The disclaimer “probable” is because it could turn out that the new particle seen at CERN is not the Higgs after all, but an imposter particle with properties like the Higgs.)

For a few days it was common to see, hear, or read my colleagues struggling to explain why the discovery of a Higgs particle is a triumph for science.  But after a week of physics in the news, the media has moved on to cover the Tom Cruise-Katie Holmes divorce and shark sightings near beaches.  Perhaps all the public will be left with is a memory that there was a triumph for science.  Science works: theories are tested and confirmed by experiment.

I think that the CERN Higgs discovery was, indeed, a triumph for science.  However, the Higgs was not the only dramatic announcement at CERN in the past year.  But the other dramatic result is something many physicists would rather forget. Read More »



Bring Your Questions for Alex Stone, Author of Fooling Houdini

I get sent about 200 books a year by strangers who want me to provide blurbs.  About 199 out of those 200 will walk away empty-handed.   Most of the time I don’t even open the book – it would be a full-time job just to read everything sent my way.  Occasionally a subject will really interest me, and I will spend some time with a book, but certainly not read it from cover to cover.  And about once a year, I actually start reading one of these books and like it so much I can’t put it down. 

That book is Fooling Houdini: Magicians, Mentalists, Math Geeks, and the Hidden Powers of the Mind , by Alex Stone.  I happened to receive the book not long after I blogged about a book by two mathematicians on the mathematics of magic.  That mathematics book was excellent and taught me a lot, but wasn’t exactly a page turner.  In contrast, the first 30 pages of Fooling Houdini was some of the most engaging non-fiction I’ve read in a long time. Read More »



Is The Big Bang Theory Producing More Physics Majors?

That’s the (tenuous) claim of this Guardian article:

According to the Higher Education Funding Council for England (HEFCE), there was a 10% increase in the number of students accepted to read physics by the university admissons services between 2008-09, when The Big Bang Theory was first broadcast in the UK, and 2010-11. Numbers currently stand at 3,672. Applications for physics courses at university are also up more than 17% on last year. Philip Walker, an HEFCE spokesman, said the recent spate of popular televisions services had been influential but was hard to quantify.

Hard to quantify, indeed.

FWIW, we’ve been told by a lot of youngish readers that Freakonomics and SuperFreakonomics led them to major in economics. John J. Siegfried addressed this possibility in a Journal of Economic Education paper called “Trends in Undergraduate Economics Degrees, 1991-2010″: Read More »



A Freaky Human Flying Squirrel Video

Our friend Annitra Morrison sent in this video the other day, and I’ve watched it at least a dozen times. It’s by professional BASE jumper, wingsuit flyer, and all around crazy person Jeb Corliss, whom you might remember from 2006, when he was arrested on the observation deck of the Empire State Building, restrained by the NYPD before he could BASE jump off of it. My question after watching this video is: how many physics calculations did Corliss and Co. do before he took the giant leap? And also, considering how close he comes (watch at the 1:19 mark, don’t worry you’ll get a few looks at it) was he correct? Read More »



The Physics of Putting

I always love it when I’ve been doing something one way my whole life, and then someone explains to me there is a better way to do that same thing, and the new way is so simple I can immediately switch and see benefits.

Usually it is a new technology that unlocks the magic. For instance, XM Radio, iTunes and Pandora all fundamentally changed the way I listen to music. My Sonicare toothbrush is a hundred times better than a regular toothbrush. After the creation of seedless watermelons, I would never again intentionally buy one that had seeds. Microwave popcorn is another example.

What is even neater, I think, than a new technology changing things, is when someone just comes up with a better way of thinking about a problem. I’ve done a little bit of reading on the origins of randomized experimentation, and it is fascinating to see how that new and powerful idea emerged.

On a much smaller scale, I’ve recently had that sort of change in my thinking about another issue: how to read putts on the green when playing golf. Read More »



Volvo XC60: A New Green Machine? Not Exactly

I was recently traveling in Europe (including in Switzerland, where 87% of trains are less than 3 minutes late). While I was in Cambridge, England, my old friend and colleague David MacKay, who shares my antipathy to bad numbers, gave me a copy of a recent article in the UK journal Physics World (“Optoelectronics: a green explosion”, May 2011, p. 5 of the optics supplement). The article touted laser-based “green technologies,” including their use in reducing carbon-dioxide emissions:

Volvo’s Johnny Larson says it is possible to shave a few kilograms off the weight of a car’s metal frame by optimizing its design for a laser process. This has knocked up to 2 kg [4.4 lbs] off the XC60, and for every one of these models that clocks up 100,000 km [60,000 miles], 24 kg [53 lbs] of carbon-dioxide emissions will be saved.

So many numbers, so little meaning! Whenever I see so many numbers, I think of what Socrates might have said: “The uncompared number is not worth knowing.” Let’s start with the 2-kg weight reduction. Read More »