Physics
esiegel | February 12, 2010However time may be measured at the Naval Observatory, the clock seems to tick slowly here when Congress is out of town. -Richard Corrigan
The following is the mostly true (but somewhat fictionalized) story of the first clocks in the Americas. In the 17th Century, the finest clockmakers in the world were Dutch, going back to the time of Christiaan Huygens.
Image: A Dutch Longcase clock, courtesy of The Museum of the Dutch Clock.
Huygens determined that if you allowed a pendulum to swing just a little bit, the period of its swing could be used to keep time to incredible accuracy. By the mid-…
pontiff | February 12, 2010In the New York Times today there is an interesting article about Helene Hegemann whose debut novel, "Axolotl Roadkill," drew wide praise. You know this story: turns out that the book contains plagiarized passages (plagiarism: check, sales rising: check.) What I find fascinating about the story, however, is not this rehash of a tried and true marketing tactic, but Ms. Hegemann's defense of herself, summarized in this quote:
"There's no such thing as originality anyway, just authenticity," said Ms. Hegemann in a statement released by her publisher after the scandal broke.
Why do I love this…
drorzel | February 12, 2010What's the application? Optical tweezers use focused light beams to trap small particles in the focus of the beam, and drag them around by moving the beam.
What problem(s) is it the solution to? 1) "How do we move these tiny little things around without touching them?" 2) "How do we measure the forces exerted by biological molecules?" 3) "How do we tie knots in DNA strands?"
How does it work?The basic optical tweezer scheme uses a single beam of light focused down to a very small spot. If you take some small (mostly) transparent object and place it in the beam, it will feel a force pulling it…
drorzel | February 12, 2010There have been a bunch of stories recently talking about quantum effects at room temperature-- one, about coherent transport in photosynthesis , even escaped the science blogosphere. They've mostly said similar things, but Thursday's ArxivBlog entry had a particular description of a paper about entanglement effects that is worth unpacking:
Entanglement is a strange and fragile thing. Sneeze and it vanishes. The problem is that entanglement is destroyed by any interaction with the environment and these interactions are hard to prevent. So physicists have only ever been able to study and…
drorzel | February 12, 2010Miscellaneous stories and links about How to Teach Physics to Your Dog:
-- There's a nice review by Margaret Fisk (who has been reading it for a while, and mentioning it on her blog, which kept turning up in the vanity search):
Orzel does a wonderful job of finding physical parallels to explain quantum concepts in ways that make a reasonable amount of sense, whether in the behavior of dogs on a walk or the "magically" refilled food bowl. Though scientifically inclined, through a series of events I ended up with little formal training, and this book is written for people in just that situation…
drorzel | February 11, 2010What's the application? Measuring the distance from the Earth to the Moon by bouncing a laser off one of the retro-reflector arrays left there by the Apollo missions.
What problem(s) is it the solution to? 1) "How does the distance from the Earth to the Moon vary over time due to things like tidal drag?" 2) "Does the strength of gravity change over time?" 3) "What can we do with a laser to really cheese off people who think the Moon landings were fake?"
How does it work? This concept is simplicity itself. You simply point a laser at the Moon, fire off a short pulse of light, and wait for it…
esiegel | February 10, 2010The New Age? It's just the old age stuck in a microwave oven for fifteen seconds. -James Randi
About two weeks ago, the WMAP (Wilkinson Microwave Anisotropy Probe) team released their seven-year results, and I'm finally ready to tell you all about it. WMAP, remember, is this guy.
By looking at two different points in the sky simultaneously, and looking at the proper frequencies of microwave light (it looks at five different frequencies every time it looks at the sky), it can measure the differences in the intensity of light left over from the big bang everywhere in the sky. Why is this so…
drorzel | February 10, 2010What's the application? Using lasers to reduce the speed of a sample of atoms, thereby reducing their temperature to a tiny fraction of a degree above absolute zero.
What problem(s) is it the solution to? 1) "How can I make this sample of atoms move slowly enough to measure their properties very accurately?" 2) "How can I make this sample of atoms move slowly enough for their quantum wave-like character to become apparent?"
How does it work? I've written about laser cooling before, but the nickel version of the explanation is this: You can think of a beam of light as being made up of photons…
grrlscientist | February 9, 2010tags: NASA, Endeavour, International Space Station, spaceship launch, STS-130,Kennedy Space Center, space exploration, physics, astronomy, engineering, streaming video
Space shuttle Endeavour, carrying Commander George Zamka, pilot Terry Virts, and Mission Specialists Nicholas Patrick, Bob Behnken, Steve Robinson and Kay Hire, successfully launched from the Kennedy Space Center in the early hours of February 8, headed for its 13-day STS-130 mission to the International Space Station.
esiegel | February 8, 2010Ever since I was a child I have had this instinctive urge for expansion and growth. To me, the function and duty of a quality human being is the sincere and honest development of one's potential. -Bruce Lee
It isn't only our heros that expand and grow; the Universe does that, too! In the first three parts of our series, we talked about inflation, its end, and the hot big bang. But during all of this time, the Universe has been expanding.
This is probably the most confusing aspect of cosmology, so tread slowly through this. First off, it is space itself that is expanding. It doesn't make…
drorzel | February 8, 2010What's the application? The use of lasers to provide an entertaining light show for humans, dogs, or cats.
What problem(s) is it the solution to? 1) "How will I entertain my dog or cat?"
2) "How can we distract people from the fact that Roger Daltrey has no voice left?"
Why are lasers essential? Lasers provide coherent beams of light, which remain small over very large distances, allowing you to project a small spot or a tight beam across a room, or even a football stadium.
Why is it cool? Duuuuude! Lasers, duuuuude!
Why isn't it cool enough? 1) It's fundamentally just a toy. 2) No amount…
drorzel | February 8, 2010A couple of weeks ago, I announced a contest to determine the Most Amazing Laser Application. After a follow-up post listing the likely candidates, we have a final list of candidate applications, an even dozen of them (after consolidating some related topics):
Cat toy/ dog toy/ laser light show
Laser cooling/ BEC
Laser ranging/position measurement
Optical tweezers
Optical storage media (CD/DVD/Blu-Ray)
LIGO
Telecommunications
Holography
Laser ignited fusion
Laser eye surgery
Laser frequency comb/ spectroscopy
Laser guide stars/ adaptive optics
Here's how this will work: over the next week…
drorzel | February 7, 2010My talk at Maryland last Thursday went pretty well-- the impending Snowpocalypse kept the audience down, as people tried to fit in enough work to compensate for the Friday shutdown, but the people who were there seemed to like it, and asked good questions. If you weren't there, but want to know what I talked about, here are the slides on SlideShare:
Talking to My Dog About Science: Why Public Communication of Science Matters and How Weblogs Can Help
View more presentations from Chad Orzel.
This flattens out some of the more animation-dependent jokes, but gets you the basic idea. It is, of…
drorzel | February 7, 2010Miscellaneous stories and links about How to Teach Physics to Your Dog:
Kathy Ceceri, who wrote the story about the book that ran in the Times Union, has posted the full article on the Home Physics blog. The link to the paper itself may very well disappear behind a paywall, but this post should remain accessible.
There's an article in the Chronicle of Higher Education that I can't read because I'm not a subscriber, and I don't remember the password needed to access it via the library subscription. If anybody has access and would like to tell me what it says, that would be cool. (UPDATE: I've…
drorzel | February 6, 2010I want to like this book more than I do.
As a general matter, this is exactly the sort of science book we need more of. As you can probably guess from the title, Why Does E=mc2? sets out to explain Einstein's theory of relativity, and does an excellent job of it. It presents a clear and concise explanation of the theory for a non-scientific audience, using no math beyond the Pythagorean Theorem.
I picked this up partly as research of a sort-- if there is ever a How to Teach Physics to Your Dog 2: Canine Boogaloo, the most obvious topic for it would be relativity, which I mention a few times,…
drorzel | February 6, 2010A couple of things happening in the next week, for those who would like some How to Teach Physics to Your Dog.
On the radio side, I am scheduled for an interview at 6:30 this Tuesday, Feb. 9, on KSOO's Viewpoint University. If you don't happen to be in the Sioux Falls, SD area, they do have a "Listen Live" button on their web page.
On the live-action side of things, I will be at Boskone next weekend, and am scheduled to sign books at 1pm Saturday, and to do a reading at 9:30 am Sunday. I realize that's sort of early in con world, so to make it worth your while to get up that early, I plan to…
rallain | February 5, 2010The following is a collection of some of my posts that can be put into a simple and quick textbook-type thingy. I am not really sure you would call this a textbook, but maybe you would. This does not include everything you would normally find in a traditional textbook, but clearly it is not traditional. I tried to keep it to just the fundamental ideas. As I write more stuff that is appropriate, I will add it.
In terms of the level of this material, I would think it would be appropriate for advanced high school physics or introductory college-level physics.
I plan to update this list with…
esiegel | February 3, 2010Nobody can go back and start a new beginning, but anyone can start today and make a new ending. -Maria Robinson
In parts one and two, we covered the very beginning of the Universe as we know it. Specifically, we talked about inflation, which is the process that sets up the Big Bang. Inflation -- to recap -- expands the Universe exponentially fast, driving the matter density to zero and stretching the Universe flat like a balloon getting blown up supremely fast.
But inflation ends, and when it does, all of that stored (i.e., potential) energy that was being used to expand the Universe now…
drorzel | February 3, 2010It's been a while since I've done a fun with graphs post about the Amazon sales rank of How to Teach Physics to Your Dog, but that's not because I've stopped tracking it. It's getting to be enough data, though, that it's worthwhile to look on a slightly coarser scale, so here's the sales rank data binned by day:
This shows some clear structure, specifically two points with dramatic drops (that is, dramatic improvements in the Amazon rank-- smaller numbers are better), followed by slow climbs. The two big improvements correspond to the immediate post-publication blog boost, and the…
drorzel | February 3, 2010Yesterday's post on a variation of the "Twin Paradox" with both twins accelerating was very successful-- 337 people voted in the first poll question, as of a little before 9am, and the comments to the original post are full of lively discussion. That's awesome.
I wish I could take credit for it, but the problem posed is not original to me. It comes from a 1989 paper in the American Journal of Physics, which also includes the following illustration setting up the situation:
The article contains a full explanation, and also the following figure illustrating the result:
The correct answer is…