Physics
esiegel | May 17, 2013"Anyone who has never made a mistake has never tried anything new." -Albert Einstein
Back when Einstein first proposed his theory of General Relativity, his revolutionary picture of the Universe was met with a mix of curiosity, awe, and intense skepticism. It isn't every day that your most cherished of all physical theories -- the theory of Newtonian Gravity that had ruled the cosmos for nearly two-and-a-half centuries -- gets challenged by a newcomer.
Image credit: Brooks/Cole - Thomson publishing, 2005.
And yet, that's exactly what Einstein did when he proposed General Relativity at the…
drorzel | May 16, 2013There's a famous story about Richard Feynman at Cornell suffering from the science equivalent of writer's block, after WWII. He was depressed and feeling like everything he did was pointless, until one day he spotted a student throwing a plate up in the air in the cafeteria. As the plate spun, it wobbled, and the wobble seemed to go faster than the spin. Intrigued, he sat down and calculated the physics involved, finding that, indeed, the wobble should go at twice the rate of spin. This basically reignited his interest in physics, and shortly after that, began his legendarily productive…
esiegel | May 15, 2013“Supposedly she’d died, but here she was again–somewhat changed, but you couldn’t kill her. Not when the truest part of her hadn’t even been born.” -Denis Johnson
Over the past 100 years, our picture of the Universe has changed dramatically, on both the largest scales and the smallest.
Image credit: Richard Payne.
On the large-scales, we've gone from a Newtonian Universe of unknown age populated only by the stars in our own Milky Way to a Universe governed by General Relativity, containing hundreds of billions of galaxies.
Image credit: Rhys Taylor, Cardiff University.
The age of this…
drorzel | May 14, 2013One of the perennial problems of teaching intro physics is getting students to do their homework, so I was very interested to see Andy Rundquist on Twitter post a link to a paper on the arxiv titled "How different incentives affect homework completion in introductory physics courses." When I shared this with the rest of my department, though, I got a link to an even more interesting paper from the same group, on the effect that doing homework has on student performance. This has an extremely surprising conclusion: for the weakest students in introductory physics, doing more homework actually…
esiegel | May 10, 2013"As seismologists gained more experience from earthquake records, it became obvious that the problem could not be reduced to a single peak acceleration. In fact, a full frequency of vibrations occurs." -Charles Francis Richter
You've all been around long enough to be familiar with the severe damage that earthquakes can cause, rattling and cracking the ground, shaking down buildings, and creating catastrophic tsunamis tidal waves. In short, the largest ones that occur in the wrong places will cause billions of dollars worth of damage and will kill thousands of people.
Image credit: AP / Press…
drorzel | May 10, 2013The book-in-progress (which is coming along, albeit slowly, thanks for asking) is built around making analogies between scientific discoveries and ordinary activities. This necessarily means telling a lot of historical stories, which is both good and bad. The bad part is that actual history is way messier than the streamlined version you get to use if you're primarily trying to explain the science, and I feel some obligation to do this right as much as possible, thus making work for myself. The good part is I'm reading a lot of narrative history of science stuff, which is kind of fun. In…
esiegel | May 8, 2013"No valid plans for the future can be made by those who have no capacity for living now." -Alan Watts
"They do not see what lies ahead, when Sun has faded and Moon is dead." -J.R.R. Tolkien
One of the most amazing facts about the Universe is that, despite only having spent a few hundred years studying the fundamental constituents and forces of what makes us up, humanity has been able to accurately figure out just what all this actually is.
Image credit: ESO / S. Brunier.
The laws of nature are almost completely understood in a few, very important senses. We know that our Universe is about…
drorzel | May 8, 2013My 20-year college reunion is coming up at the start of next month (at the end of the week of DAMOP in Quebec-- I'm going to be completely wiped out...), so I've been thinking a bit about nostalgia. A little while back, the subject of reunions came up on an email list, and somebody trotted out the classic "Those are the best four years of your life" line. This produced a definite split, with some people scoffing at the idea that college or high school could legitimately be considered the "best," while a couple argued that it's not necessarily ridiculous on the face of it: after all, you're…
drorzel | May 6, 2013My parents have a DVD of the Bacon Brothers singing "The Wheels on the Bus" over an animated scene, which The Pip loves and insists on watching over, and over, and over, and over... As the parent sitting through this on Sunday morning, I got a little punchy over on Twitter, and invented some quantum-physics-themed verses (if you don't know the tune, 1) count yourself lucky, and 2) here's a clip from the video on YouTube). Here are the results:
The electrons on the bus are fermions,
fermions,
fermions.
The electrons on the bus are fermions, in antisymmetric states...
Operators on the bus are…
catdynamics | May 3, 2013Just read a series of interesting articles on inquiry based science:
Inquiry Science rocks: Or does it - David Klahr tries to test the efficacy of discovery learning (APS News 12. 2012).
Direct Instruction rocks: Or does it - Richard Hake takes issue with Klahr's inferences.
To be contrasted with:
The Efficacy of Student-Centered Instruction in Supporting Science Learning - Granger et al Science 338 105 (2012) [sub]
The amount of data on the efficacy of the different teaching methods is still pathetically small.
I am inclined to believe that student center instruction or inquiry science is…
esiegel | May 3, 2013“Talent hits the target no one else can hit; genius hits the target no one else can see.” -Arthur Schopenhauer
You've probably heard the story, by now, of Kiera Wilmot, the 16-year-old girl who performed a mildly dangerous chemistry experiment on school grounds, mixing together household cleaner and aluminum inside a sealed container. You can get the full story (excellently covered) via DNLee, but to give you the 15-second version, she was arrested, expelled, and is presently being charged with a felony that carries up to 5 years in prison. The school board is not backing down, the attorney…
drorzel | May 2, 2013Erwin Schrödinger is one of the more colorful figures in physics history. He's best known for Emmy's favorite thought experiment, of course, which attempts to demonstrate the absurdity of quantum physics through locking a cat in a box. This overshadows the Schrödinger Equation, the central equation of non-relativistic quantum mechanics, which won him a Nobel Prize in 1933. He's also renowned within physics for his unorthodox personal life, which involved innumerable extramarital affairs, and ultimately cost him a job at Oxford.
The definitive academic biography of Schrödinger has been out for…
esiegel | May 1, 2013"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality." -Hermann Minkowski
When it comes to gravity, you probably think you understand it pretty well.
Image credit: Heavens Above, via http://heavens-above.com/.
Everything with mass (or energy) attracts everything else with mass-or-energy, explaining everything from falling…
drorzel | April 29, 2013Last year, Alan Alda posed a challenge to science communicators, to explain a flame in terms that an 11-year old could understand. this drew a lot of responses, and some very good winners. This year's contest, though still called the "Flame Challenge," asked for an answer to the question "What Is Time?"
This is a little closer to my corner of science, so I considered entering, but as previously noted, I'm crushingly busy at present. And either scripting/ shooting/ editing a video, or doing the necessary work to hack a written response down to the prescribed 300 characters was more time than I…
jdupuis | April 28, 2013hardly ever does The Globe and Mail books section every Saturday feature more than one, maybe two, books that I'm interested in. They're pretty heavy on the Canlit side, with a heavy helping of the kind of public affairs books that don't really do it for me. The mystery roundup feature is usually my best bet. Well this week there were three -- count'em three -- books that really piqued my interest. And a pretty diverse bunch too, one physics, one horror fiction and another environmental non-fiction featuring the kind of intersection between food, science and policy that I find so interesting…
esiegel | April 26, 2013"All our sweetest hours fly the fastest." -Virgil
If you've been around the block once or twice, you know that the speed of light in a vacuum -- 299,792,458 meters-per-second -- is the absolute maximum speed that any form of energy in the Universe can travel at. In shorthand, this speed is known as c to physicists.
Image credit: user Fx-1988 of deviantART.
But you or I, no matter how hard we try, will never attain that speed. There's a simple reason for this: we have mass. And for an object with mass, you can accelerate it all you want, but it would take an infinite amount of energy to…
esiegel | April 24, 2013"Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." -Douglas Adams
Well, maybe "peanuts" isn't going to do. When you look out at the night sky, all sorts of objects are yours to discover, from our closest neighbors in the Solar System to the billions of stars in the Milky Way to the faint, extended and fuzzy galaxies stretching millions and billions of light years across the cosmos.
Image credit: Stephane Guisard, via http://sguisard.astrosurf.com/.
But…
drorzel | April 24, 2013The playground outside SteedlyKid's day care, amazingly in this litigious age, has a merry-go-round, a rotating disc with a really good bearing. The kids can really get the thing flying, which is kind of terrifying at times. But on the bright side, it's an excellent venue for the physics of angular momentum:
In the embedded video, SteelyKid runs in and starts the merry-go-round spinning, then jumps aboard and goes around one full rotation before moving to the center for a few rotations, and then starting to move back out.
This isn't exactly what I was hoping for-- amazingly, a four-and-two-…
esiegel | April 19, 2013"Despite its name, the big bang theory is not really a theory of a bang at all. It is really only a theory of the aftermath of a bang." -Alan Guth
So you finally understand it. The Big Bang tells us that the Universe was hotter, denser, and expanding at a faster rate in the past.
Image credit: original source unknown.
The farther back we go, the closer together everything was, the higher in temperature (and shorter in wavelength) all the radiation was, and -- of course -- the younger the Universe was.
Image credit: Ned Wright (possibly Will Kinney, too), via http://ned.ipac.caltech.edu…
drorzel | April 18, 2013A couple of days ago, Alom Shaha posted on the new Physics Focus blog (by the way, there's a new Physics Focus blog...) about his dissatisfaction with some popular books:
I recently read a popular science book on a topic that I felt I needed to learn more about. The book was well written, ideas were clearly explained, and I finished the book knowing a lot more about the history of the subject than beforehand. However, I don’t feel I understand the key ideas in the book any better. I won’t mention the name of the book or the author because this post isn’t really about that specific book. It’s…