Physics
catdynamics | March 17, 2014Imagine you were a very clever ant, living on a large log, floating in a big lake...
BICEP2 at twilight
...a very large, deep, cold lake.
Being a not incurious, clever ant, you contemplate the lake in its infinite and insurmountable vastness.
Surely knowing what lies on the lake, or even beyond the lake (if such can be conceived) is not feasible.
Then, you notice that the lake has ripples.
Ripples, and waves, and swirls.
So, being a methodical sort of ant, you start measuring the ripples and waves and swirls, and you get your student ants to measure them also.
You measure lots of waves,…
drorzel | March 17, 2014This week's Cosmos was all about the evolution of life, and was viewed by millions of people outside of Oklahoma, where they presumably got an hour-long local news promo, or analysis of the Oklahoma State's chances in the NCAA Tournament. As such, it was a bit outside my area of expertise, but that never stopped a blogger before...
There were a couple of things about this that I thought were great, and two things that bothered me. The episode opened with a very nice discussion of the history of dogs and humans, demonstrating how dramatically untold generations of human selection have modified…
drorzel | March 14, 2014The other big nerd event of today is that it's Einstein's birthday, on this date back in 1879. I keep meaning to take and post a photo of the cool picture of Einstein we have in the department's collection of stuff, and this is as good an excuse as any.
Charcoal drawing of Einstein giving a talk in Schenectady in 1939. The original is in the Department of Physics and Astronomy office, donated by Carl George, who I think got it from the artist originally.
If not for him, we wouldn't have anything to sarcastically call smart people who do dumb things. Oh, yeah, and the whole General…
drorzel | March 14, 2014Today is March 14th, 3/14 in the normal American way of writing dates, so you'll find a lot of silliness on the web today talking about "π Day" due to the coincidental similarity with the first three digits of π (see, for example, Rhett's annual post). But, of course, this is an archaic and local convention, and not really suited to the dignity of science.
After all, the defined SI unit of time is the second, so if you're going to do things properly, you really ought to measure time in seconds (like the Qeng Ho in Vernor Vinge's brilliant A Deepness in the Sky). So, a proper celebration of…
drorzel | March 13, 2014"So, that's the science show with space pictures. What did you think of it, honey?"
"Science. Space pictures. Awesome!"
Our umpteenth winter storm of the season delayed school two hours this morning, which is kind of the worst of all possible worlds from a parenting perspective-- when the schools are closed, there's (usually) a snow-day day-care program, but they don't take kids during a mere delay. On the bright side, though, it gave me a chance to show SteelyKid the Cosmos reboot from Sunday night. Her capsule review is at the top.
In a little more detail:
-- I asked her if she wanted to…
drorzel | March 13, 2014So, last week I idly wondered about the canonical falling-bomb whistle. The was originally intended to be a very short post just asking the question, but I got caught up in thinking about it, and it ended up being more substantial. And leaving room for further investigation in the form of, you guessed it, VPython simulations.
This one isn't terribly visual, so you don't get screen shots, just a link to the code at Gist. It's a simulation of a falling bomb, with air resistance, tracking the velocity as a function of time. Then it calculates a "Doppler shift" using the velocity as a fraction of…
drorzel | March 11, 2014In which Rhett and I talk about Cosmos. What, you thought there would be another topic? We have contractual obligations, you know...
Okay, there were some other topics like Battlestar Galactica (both versions), why so much of what's on Discovery Channel and TLC sucks these days, the flawed astrophysics of Firefly, speculation about how those little infrared thermometers work, and why some kinds of labs are hard.
And Cosmos again. Because, really, how could we not?
drorzel | March 10, 2014It says here in the fine print that my blogging license could be revoked if I fail to offer a public opinion on the Cosmos reboot, which premiered last night. I missed the first couple of minutes-- I had The Pip for bedtime, and he didn't start snoring until 8:58-- but saw most of it in real time. I posted a bit of commentary on Twitter, but will offer something marginally less ephemeral here.
The show opened and closed with tributes to Carl Sagan, and Neil deGrasse Tyson standing on the same cliff where Sagan opened the original series back in 1980. That was good and fitting, and Tyson's…
drorzel | March 7, 2014Not that long ago, SteelyKid was doing something violent with toys (she's very tough, as you can see from the featured image above), and in the process made the canonical falling-bomb whistle noise. And it occurred to me to wonder, why that sound?
I mean, I've seen footage of falling bombs and the canonical sound seems like an accurate enough. But I'm not sure I understand it from a physics perspective. Specifically, when you do the falling-bomb whistle, you do a whistle that decreases in pitch. But the bomb is falling faster as it approaches the ground, so if anything, I would expect the…
esiegel | March 6, 2014“All the problems of the world could be settled easily if men were only willing to think. The trouble is that men very often resort to all sorts of devices in order not to think, because thinking is such hard work.” -Thomas J. Watson
You’ll frequently hear people say, “the science is settled.” Scientifically speaking, can it ever be? (And yes, what follows below is meant to be an inflammatory image.)
Image credit: Ramirez of the Weekly Standard, via http://www.IBDeditorials.com/cartoons.
Let's take a look at five major instances -- gravitation, evolution, the Big Bang, germ theory and…
drorzel | March 6, 2014Given the academic circles I run in, it's not surprising that one of the most repeated stories crossing my social media feeds yesterday had to do with the changes to the SAT. Starting in 2015, the essay section will no longer be mandatory, and they're going to reconfigure the reading and math sections to emphasize different categories of questions.
My slightly cynical take on this is that changes seem to be driven more by marketing than education-- stories about this all mention that the changes make the new SAT more like the ACT, which has been gaining in popularity in recent years. Which…
drorzel | March 4, 2014In which we move out of the original trilogy, and into J.J. Abrams territory. Cue the lens flare!
This week's random assortment of topics includes travel, airports, physics models of loading and unloading planes, uses and abuses of curve fitting, odd stuff we get sent to review, and high-speed video cameras.
Miscellaneous links:
-- Rhett's Atlanta airport post.
-- The airplane loading study I was thinking of is Optimal boarding method for airline passengers, by Jason Steffen, from 2008.
--The Slo Mo Guys, Smarter Every Day, Veritasium.
--Trespassing on Einstein's Lawn by Amanda Gefter.
That'…
drorzel | March 4, 2014In October 1988, I trashed my parents' basement in order to get into college.
OK, the causal connection is a little indirect, but it's there. I was applying to college that fall, and needed to write an essay to go with my application. I've always been able to write stuff with very little effort, so I banged out something that I thought was adequate, and showed it to my guidance counselor, who said "No way." My parents backed her up on this, and I had to go write another one.
The problem was that while what I had written was reasonably polished, it was also glib and superficial-- because I'm…
drorzel | March 3, 2014This year's "Flame Challenge" asks scientists to explain color in terms an 11-year-old can understand. The rules limit answers to either 300 words of text or a 6-minute video. 300 words is ridiculously short, so video is clearly the way to go. Of course, I'm not much of a video expert, but then, one of the finalists last year (when the question was "What Is Time?") was just a guy talking into a webcam, and hell, I can do better than that. So I did this:
(This is, obviously, why I was fooling around with looking at the spectrum of light from my laptop a little while back...)
The approximate…
esiegel | February 28, 2014“You can’t get there by bus, only by hard work and risk and by not quite knowing what you’re doing. What you’ll discover will be wonderful. What you’ll discover will be yourself.” -Alan Alda
Alan Alda recently challenged scientists to explain this simple question to 11-year-olds in less than 300 words. Could you do it?
It seems like a straightforward enough proposition; after all, we surely know it when we see it.
Image credit: Jessica at Ways of Wanderers, via http://waysofwanderers.com/colourful-flower-fields-biei/.
But there are some very tight constraints on this contest: you must be…
drorzel | February 28, 2014I got book edits this week, gave an exam on Thursday, and pre-registration for our spring term classes is just beginning, so I have a parade of students begging to get into this course or that one to deal with. So I have no more time for detailed blogging, but will do a bit of tab-clearing to end the week.
This piece about bimodal exams resonated well with my experiences in intro classes. I see a lot of the same thing, though with less statistical power, given that our maximum class size is 18. But in general, the "well-prepared students are bored, poorly-prepared students hopelessly lost"…
esiegel | February 27, 2014“If you are caught on a golf course during a storm and are afraid of lightning, hold up a 1-iron. Not even God can hit a 1-iron.” -Lee Trevino
It’s one of the most beautiful (and terrifying) sights in the world. But what causes it?
If the Earth is about to spew volcanic ash, smoke, soot and even lava from deep within its bowels at us, the least it could do is not electrocute us at the same time. Right?
Image credit: Sigurður Hrafn Stefnisson of http://www.stefnisson.com/.
Yet over 150 separate volcanic eruptions have been recorded with volcanic lightning accompanying them. But there are…
drorzel | February 27, 2014Last week, we looked at the resistance of a voltage sensor by using the discharge of a capacitor, getting a value that was a bit high, but not wildly out of line with the specs. This time out, we're going to look at the resistance of a current meter, because some students asked about it during Wednesday's exam review session.
The question came up because one of the things I have on the standards for the circuit portion of the class is knowing how to hook up a current meter and a voltage meter in the appropriate ways. This is strangely confusing for a lot of students, which gets annoying, as…
drorzel | February 26, 2014Matt Reed, who will forever be "Dean Dad" to me, has a post on "new" topics that might be considered for "gen ed" requirements, that is, the core courses that all students are required to take. This spins off a question Rebecca Townsend asked (no link in original), "Should public speaking be a general education requirement?" the idea being that public speaking is such an essential skill that everyone ought to learn it at some point. Reed adds "entrepreneurship," "[computer] coding" and "personal finance" as other things that might fall into the same essential category.
Now, it's important to…
drorzel | February 25, 2014This week's episode of Uncertain Dots is, if anything, even more free-form than previous weeks, including a brief cameo from one of Rhett's kids:
Topic covered include the arrangement of faculty offices, the relative lack of demos for E&M (compared to mechanics, where there are endless videos to analyze, etc.) a little bit about science journalism and sports journalism, how we deal with (or don't) the problem of including background information in our blogs, the need to sometimes bring your kids to campus or cancel classes, teaching while sick, tracking the flu, precision measurement and…