Physics
drorzel | April 14, 2010I won't attempt to explain the chain of reasoning that led to this topic this morning. The poll itself doesn't need much explanation, though: As any geek knows, the tv show(s) CSI: Descriptive Subtitle rely heavily on fake technologies. which of these would you most like to be real?
Which imaginary technology from CSI would you rather have?online surveys
Yes, I have read the relevant xkcd comic. Personally, I lean toward the image enhancement, because if we had their image processing capability attached to the Hubble, we'd be mapping continents on Earth-like planets in the Andromeda Galaxy…
oracknows | April 14, 2010With all the anti-vaccine nonsense going on and my feeling the obligation to fire a broadside at "America's doctor," there was a tasty bit of woo that totally escaped my attention from an old "friend" of the blog. Actually, he's an old "friend" of many skeptical blogs, both here on ScienceBlogs and around the blogosphere. In fact, it's a man so steeped in only the finest quantum woo that I once coined a name for it: Choprawoo.
Yes, we're talkin' Deepak "Quantum Consciousness" Chopra! He's back and woo-ier than ever in--where else?--that repository of woo, quackery, and anti-vaccine lunacy,…
rallain | April 13, 2010Suppose I take a 1 kg ball and hold it near the surface of the Earth. What would be the gravitational force the Earth exerts on this ball?
And I could say "g" is:
The magnitude of this force would then be 9.8 Newtons. And, if I replaced the ball with a 10 kg ball, the force would be 98 Newtons. What does this have to do with the electric field? Well, you are probably already familiar with this idea of the gravitational force. Guess what? "g" is the gravitational field. Basically, it is the force per unit mass due to the Earth. This is only approximately constant. If I get very far…
drorzel | April 13, 2010I am currently on a committee looking to set some standards for technical writing in the introductory engineering sequence (which means the first two terms of physics, as they constitute 50-67% of the classes common to all first-year engineers). One of our jobs is to come up with a list of skills that we want to particularly emphasize in student writing in the first year.
I've already sent this query to my colleagues, who are the votes that really matter, but this seems like a worthy subject for a blog poll. If nothing else, it will be interesting to see if my wise and worldly readers prefer…
drorzel | April 13, 2010I'm teaching a junior/senior level elective this term on quantum mechanics. We're using Townsend's A Modern Approach to Quantum Mechanics, which starts with spin-1/2 and develops the whole theory in terms of state vectors and matrices. This is kind of an uneasy fit for me, as I'm very much a swashbuckling experimentalist, and not as comfortable with formal mathematics.
This occasionally leads to good things, though, such as Monday's class, on photon polarizations. the book uses some vector arithmetic to show that circularly polarized photons have spin angular momentum of one unit of h-bar.…
esiegel | April 12, 2010"Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read." -Groucho Marx
"While no one has proved that wormholes exist, that does not for a moment keep the more adventurous of thinkers from trying to figure how they might behave."
-Michael Lemonick, Time magazine
Wormholes. We've all heard the word before, and we're used to the concept (thanks to science fiction) that wormholes could be tunnels to either completely different locations in space or in time!
How so? You see, when you get enough mass (or other form of energy) in a small enough space, it becomes…
drorzel | April 12, 2010What's the application? LIGO stands for Laser Interferometer Graviitational Wave Observatory, because (astro)physicists feel free to drop inconvenient words when making up cute acronyms. This is an experiment to look for disturbances in space-time caused by massive objects, which would manifest as a slight stretching and compression of space itself.
What problem(s) is it the solution to? 1) "Can we directly observe the gravitational waves that are predicted by the equations of General Relativity?" 2) "Can we detect things like colliding black holes, because that would be awesome!"
How does it…
drorzel | April 12, 2010Several weeks ago, I announced a contest to determine the Most Amazing Laser Application. Personal issues interrupted this, but I want to finish it out in honor of LaserFest Here's the list of finalists, with links to those already written up:
Cat toy/ dog toy/ laser light show
Laser cooling/ BEC
Lunar laser ranging
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
I'll be writing up LIGO shortly, and will try to finish the whole thing as soon…
rallain | April 9, 2010So, I complained about MythBuster's explanation of relative velocity. How would I explain this? I would start by saying that velocity is relative. Here is the definition for velocity:
I put the "avg" in there because it is more true. If the acceleration is zero, I could drop this. For the rest of this post, I am going to assume zero acceleration. Ok. But what is the r vector? It is simply a vector from the origin to the object. Here is a picture.
Simple, right? And so the velocity tells how this vector r changes. But wait. Who says that I used the correct origin? How do you…
esiegel | April 9, 2010"Cosmologists are often in error, but never in doubt." -Lev Landau
I've been telling you about the Big Bang, the greatest story ever told, and the entire natural history of the Universe. Let's remind you -- historically -- of how our conception of the Universe changed as we learned more about our surroundings.
Maybe the first astronomical observation ever made was that the Sun rises in the East, passes overhead, and sets in the West. And it does this day after day, every day. It's no wonder that our first "cosmological model" of the Universe was that the Earth is stationary, and the Sun…
esiegel | April 9, 2010Those of you who've been reading Starts With A Bang since this last summer may have seen this article I wrote -- The Math of the Fastest Human Alive -- about Usain Bolt's world record in the 100 meter dash.
Little did I know what type of interest this would generate. A few weeks after I wrote it, I found that my article was reprinted -- verbatim -- in the St. Petersburg Times, and then was featured in MacLean's. And I thought that was going to be it.
And then Esquire Magazine called. I'm featured on page 133 and 134 of this month's (April 2010) issue, and you can read the article online…
drorzel | April 9, 2010The National Science Board made a deeply regrettable decision to omit questions on evolution and the Big Bang from the Science and Engineering Indicators report for 2010. As you might expect, this has stirred up some controversy.
I wasn't surprised to learn this, as I had already noticed the omission a couple of months ago, when I updated the slides for my talk on public communication of science-- the figure showing survey data in the current talk doesn't include those questions, while the original version has them in there. I noticed it, and thought it was a little odd, but it had no effect…
drorzel | April 9, 2010There's no rest for the wicked, as last weekend's hectic running around is followed by another busy weekend, with some on-campus stuff on Sunday as part of our annual Accepted Students Days. More importantly, though, I will be on a panel at the Empire State book Festival on Saturday from 12:45-1:30 pm:
BLOOK: Going from Blog to Book
Empire State Convention Center, Meeting Room 4
Books derived from blogs are a publishing phenomenon of the past few years. Why is there an audience for previously digital content in analog form, and what does this say about the future of the book? Hear from a…
rallain | April 8, 2010I have made some small changes to my physics textbook. Basically, I have been updating all my old posts so that you can find stuff. What I did was include tags for each topic. For instance, suppose you are looking at projectile motion. Well, I include a link to examples with projectile motion.
Some of the examples may not be the best for that topic, but it is better than nothing. Really, what I need to do (other than finish tagging all my old posts) is to pick one good example for each topic. There is always tomorrow.
drorzel | April 8, 2010Via Twitter, Michael Barton is looking for some good books about physics. I was Twitter-less for a few days around the period of his request, and this is a more-than-140-characters topic if ever there was one, so I'm turning it into a blog post.
The reason for the request is that he's going to be working as an intern at the Einstein exhibit when it visits Portland, which makes this a little tricky, as relativity is not an area I've read a lot of popular books in (yet-- that's changing). That will make this a little more sparse than it might be in some other fields.
There's also an essential…
rallain | April 8, 2010In the last episode of MythBusters, they tried to reproduce the following experiment. Suppose you are driving in a car at 60 mph and you shoot a ball backwards at 60 mph (with respect to the car). Will the ball just drop (with respect to the ground)? Actually, it is a cool demo - I saw some Japanese show did this a while ago.
So, what is the problem? The problem is with the MythBusters' use of their terms to explain this thing. Let me look at a couple of the things they said to explain this (surprisingly, they described it several different ways). This first one is my favorite.
Bad…
drorzel | April 8, 2010Back when I was in grad school, and paper copies of journals were delivered to the lab by a happy mailman riding a brontosaurus, I used to play a little game when the new copy of Physical Review Letters arrived: I would flip through the papers in the high energy and nuclear physics sections, and see if I could find one where the author list included at least one surname for every letter of the alphabet. There wasn't one every week, but it wasn't that hard (particularly with large numbers of physicists from China, where family names beginning with "X" are more common).
Every so often, somebody…
grrlscientist | April 7, 2010tags: Light My Fire, physics, fire, weird, streaming video
Here's a short video showing a fun trick you can play with fire -- in your own home. It also is a graphic illustration as to why fires are so difficult to extinguish.
esiegel | April 7, 2010"By early 2011, [Fermilab's Tevatron] will have recorded enough data to either find the Higgs or rule it out. -New Scientist, August 2009
Sure, there's a whole lot of well-deserved hoopla about the LHC, the world's #1 particle accelerator in terms of energy! But don't forget about #2, Fermilab's Tevatron, which also holds the honor of being the first place I ever worked in physics!
Fermilab has been operating since the 1970s, and has been responsible for many of the most outstanding discoveries in the history of particle physics. Remember the standard model?
The standard model tells us that…
rallain | April 7, 2010I gave the following question on my last physical science (physical science for non-science majors) test:
Block A has a mass of 10 kg and volume of 100 cm3. Block B has a mass of 1 kg and a volume of 1 cm3. Which block has the greater density? Which block has the greater volume?
The results of this question are interesting. Of the respondents, 33 answered both parts in a meaningful way. 8 of these 33 answered that the one with the greatest density had the greatest volume (that is 24%). Most of these 24% said that 1 cm3 was greater than 100 cm3. However, there were some that said the…