Physics
drorzel | February 25, 2014I'm running errands today, so here's a quick post picking up a question from last week's Olympic physics hangout: What sport involves the least physics?
One of the kids in the classes we were video chatting with asked that, and I really like the question, though it was a struggle to answer. It's one of those questions that will ultimately be like an excessively-zoomed-in data graph-- whatever the answer, everything starts with a pretty high baseline of physics content, just because there's physics in everything.
For the Winter Olympics, my original suggestion was ski jumping, thinking it was…
drorzel | February 24, 2014Over at Backreaction, Bee takes up the eternal question of scientists vs. journalists in exactly the manner you would expect from a physicist: she makes a graph. Several of them, in fact.
It's generally a good analysis of the situation, namely that scientists and journalists disagree about how to maximize information transfer within the constraints of readership. That's a very real problem, and one I struggle with in writing the blog and books, as well. Lots of people will read content-free piffle, but if the goal is to convey good, solid science to as many people as possible, well, that's a…
drorzel | February 22, 2014I spent a while on Friday morning talking about the physics of the Olympics with a couple of science classes in Tennessee and Lawrence Norris from the National Society of Black Physicists, organized by Adam "@2footgiraffe" Taylor. This was done via a Google hangout, so the video is recorded on YouTube:
The recording seems to have mostly remained on my video feed, which is a little unfortunate. Lawrence didn't have a camera, though, so he's a disembodied voice. I liked the first question-- "What Olympic event involves the least physics?"-- though it's a tricky one to answer.
Anyway, it was a…
drorzel | February 21, 2014For the latest in our ongoing series of post where I overthink simple questions, I'd like to present the longest single continuous experiment in Uncertain Principles history, which took six and a half hours yesterday. All to answer the question in the post title.
This may seem like a waste, given that I could download a spec sheet, but it was a simple extension of yesterday's lab. I'm teaching E&M this term, and we're wrapping up the circuits portion of the class. Yesterday's lab was about the discharging of capacitors.
This is one of those concepts that sneaks in largely as a way to…
esiegel | February 20, 2014“If the Universe Is Teeming with Aliens… Where Is Everybody?” -Stephen Webb
If stars, planets, and biological processes are so common in the Universe, then where is everyone?
Image credit: NASA / Space Shuttle Atlantis mission 110.
Here on Earth, we take for granted how easy it was for life to form. Our world has been around for some four-and-a-half billion years, and the oldest records of life go back to nearly the oldest rocks: 3.8 billion years ago.
But if we ran the "experiment" of having a Solar System similar to our own form in the Universe over and over again, how many times would…
drorzel | February 20, 2014In comments to the post on computer display colors, Will Slaton notes that Mac displays emit polarized light. And, indeed, this is an inherent part of the backlit LCD technology-- the individual pixels are bits of liquid crystal between two polarizers, and an applied voltage causes the liquid crystal molecules to flip between a state where they rotate the polarization of light, and a state where they don't. In one of those configurations, the polarizers block the light, and in the other, they let it pass. By rapidly varying the voltages, you can make the pixels flash on and off in the right…
drorzel | February 19, 2014Ages and ages ago, I posted the picture that's the "featured image" above, and asked people to submit physics comments about it. Then I got distracted by a series of shiny things, and never did anything with the handful of responses I got. Because I'm a Terrible Person.
Anyway, it's long overdue, but here are the responses, with some comments from me. The first to send me something was Keith Hester, who emailed:
I find quite intriguing the lengthy unbroken --- and seemingly unsupported --- extension of snow that has slid over the left edge of the roof. The coefficient of friction between…
drorzel | February 18, 2014In which Rhett and I talk about color vision, undergraduate research projects, blog networks, outreach activities, and how thermodynamics is a lie.
Things mentioned in the discussion:
The Flame Challenge
My post about looking at computer monitors with a spectrometer
Physics Quest
I'm inadvertently doing a bit of product placement here-- the T-shirt I'm wearing is from Surviving the World, and the water bottle I'm drinking from is from the Institute for Quantum Computing in Waterloo. I expected it to be colder in my office on campus, but it was actually pretty warm, so I took off the other…
drorzel | February 18, 2014This year's "Flame Challenge" is to explain color in terms an 11-year-old can follow. I have opinions on this subject, a background in AMO physics, and access to scientific equipment, so I'm putting something together. In the course of this, though, it occurred to me to wonder how my different portable computing devices process color. And since I have access to an Ocean Optics USB4000 spectrometer, I can answer this question in more detail than anybody needs.
So, I have three principal electronic devices that I use to do computer-type things: a Moto X smartphone, an iPad, and a Lenovo…
drorzel | February 17, 2014In the previous post about luge, I mentioned that there was one thing that came up when Rhett and I were talking about this, namely why there are differences in times between racers. The toy physics model I set up last time suggests that the difference between riders is only a matter of aerodynamics-- two riders with the same mass and cross-sectional area ought to achieve the same speed. So why do they all get different times?
Well, if the sleds and other gear were all identical and locked into tracks, then mass and aerodynamics would be the entire story. But they're not-- the rules allow for…
esiegel | February 14, 2014"For the wise man looks into space and he knows there is no limited dimensions." -Lao Tzu
You know the deal: it's the end of the week, so it's time for another Ask Ethan! You've continued to send in your questions-and-suggestions, much to my delight, and I'm pleased to tell you that this week's question comes from Peter Tibbles. Peter asks about obtaining information from beyond where Einstein's theory of relativity allows us to see:
Because of the expansion of the universe there is an event horizon beyond which we can know nothing. There’s been one instance of intelligent life evolved (us);…
drorzel | February 14, 2014In the Uncertain Dots hangout the other day, Rhett and I went off on a tangent about the physics of the Olympics, specifically the luge. If you're not familiar with this, it's basically psycho sledding: people riding tiny little sleds down a curved track at 80mph.
The "featured image" above shows Erin Hamlin of the US women's luge team during a training run (AP photo from here); she went on to win a bronze medal, the US's first in individual luge, so congratulations to her. The photo gives you an idea of what's involved: tiny sled, icy track, curved walls.
(In the Winter Olympics context,…
drorzel | February 14, 2014We got over a foot of snow yesterday and today, so schools are closed. Except Union is a residential college, so we never close, which means I have to dig my car out all the same. Which I did, clearing a path to the unplowed street, then took Emmy for her morning walk. During which, of course, the town snow plows came around and filled in the end of our driveway again...
As I was digging out again, I was struck by just how far the snow had gone up the driveway-- I paced off about six meters from the edge of the road to the farthest clumps thrown up the driveway. As a way to distract myself…
drorzel | February 12, 2014I didn't advertise it heavily this time, but Rhett and I did another G+ hangout yesterday, and the video is online now:
We talked for a while about the wonders and importance of VPython coding (including some "Oh, I should totally do that..." moments), where we get post ideas (including a discussion of luge physics), briefly about how we put stuff together for posts, and a bit more about physics education research and why it's really difficult.
I had hoped to throw together a quick post about the luge thing for today, but that's probably not going to happen, so you'll have to settle for the…
drorzel | February 11, 2014Last week, Rhett did a post on animating a bouncing ball in VPython. This was mostly making a point about the distinction between real simulation and animation, along the lines of yesterday's post on social construction of videogame reality. But, of course, my immediate reaction was, "That's not how a bouncing ball looks..." This is how a bouncing ball looks:
(As you can see from the watermark, I'm trying out a new video editor...)
This is footage of four different types of balls bouncing on a lab cart in our stockroom, shot in gratuitous slow motion (240 fps) because I'm still playing…
drorzel | February 10, 2014One of the more annoying points of contention back in the days of the Sokal hoax and the "Science Wars" was an argument over social construction. This is, loosely speaking, the idea that our understanding of the world is not strictly rational and objective, but is heavily influenced by interactions with other people, and the culture in which we live. The idea originally arose in literary academia, but expanded to be applied to basically everything, including science.
At bottom, this is probably the best and most useful idea to come out of whatever collective "-ism" you want to use to refer…
drorzel | February 6, 2014A couple of days ago, John Scalzi posted a writing advice open thread, asking people to share the best advice they'd gotten on the craft of writing. There's a lot of good stuff in there, much of it fairly specific to fiction writing-- stuff about plotting, the use of synonyms for "said," how to keep track of who's speaking, etc. As someone who's very much an outsider to that side of the writing business, it's interesting to read, but not that directly useful (I do have long stretches of dialogue in the How-to-Teach books, and occasionally needed to worry about the "said" thing there, but that…
drorzel | February 5, 2014Back in the fall, I did a bunch of write-ups of old Master's theses that we found when clearing some space in a storage room. I got away from this because I was busy working on the book, but I have a few more that I pulled out to look at, and since all the other topics sucking up Internet energy at the moment are stupid or depressing, it seems like a good time to get back to these.
So, this is a thesis from 1934 by a fellow named Thomas Dietz, a combination of names that is common enough to make him less Google-able than you might want. This does seem to have been moderately significant work…
drorzel | February 4, 2014This week's hangout with Rhett Allain, in which we talk about how we got into physics, how we find stuff to read, what we enjoyed on physics blogs this week, what we do and don't like about Twitter, and the revenge of the Sith.
The specific blog posts we mentioned:
Frank Noschese's analysis of gravity in Flappy Birds
Ethan Siegel on Hawking and black holes
Bee at Backreaction on what Hawking really said
Timothy Burke on "administrative bloat" and faculty control
Dr. SkySkull on infinite series
Physics Buzz apologizing for starting the infinite series thing
Matthew Francis on polarization in…
drorzel | February 2, 2014Unless you've been marooned on a desert island for the last couple of weeks-- or, you know, foreign-- you're probably at least dimly aware that the Super Bowl is this evening. This is the pinnacle of the football season, and also the cue for lots of people to take to social media proclaiming their contempt for the Super Bowl, NFL football, or just sports in general. This can occasionally be sort of amusing, as with Kyle Whelliston's "Last Man" game, but usually, it's just kind of tedious. The AV Club has pretty much the only necessary response, namely that Nobody Cares That You Don't Care…