steuard: (physics)
Monday, March 17th, 2014 06:26 pm

So that physics announcement that I posted the rumors about happened, and it was indeed just as big of a deal as rumor had made it. Here are a few links I've found that summarize the results nicely:

This is really cool, and there are some neat, neat implications. (The data points to an energy scale for inflation that happens to be very close to the expected energy scale of grand unification of fundamental forces in simple supersymmetric models of particle physics, for instance.) It'll be great to see if this result holds up.

steuard: (lake)
Saturday, July 27th, 2013 10:36 pm
Wow: the xkcd webcomic had an entry called "Time" a while back that was notable because the image updated every hour(?), gradually telling some sort of story. Some dedicated people have been following it carefully, and it just reached "The End" in the past day or so (3099 frames total!). The story starts out pretty slow, but it builds to a strong conclusion, and it's awesome.

Here's a site where you can let all of the frames play back automatically at high speed (with brief pauses for frames with dialog or noteworthy events). It's worth watching!

Incidentally, there's clearly a lot of backstory that is never fully revealed along the way. Evidently there's a whole community trying to piece some of it together. Just as one thing to watch for, near the end you'll get to see two maps. Pay attention to the second one (and maybe tilt your head a little). Evidently even the details of the stars are important.
steuard: (physics)
Monday, August 6th, 2012 01:12 pm
This is an absolutely stunning image: the Curiosity rover spotted while descending to the Martian surface, dangling under its parachute. It took some tremendously careful calculations by the Mars Reconnaissance Orbiter team (and some good luck) to snap this shot of a fast-moving object in the few moments available (they had to aim the camera in advance, tell it when to take the shot, and hope). The Bad Astronomer gives a bit more detail. (Click the image for a larger version.)


(Image via NASA/JPL/University of Arizona )

I honestly yelped out loud with glee when this image showed up on my screen. (Good thing my office door was closed.)

I'm still in awe that this insanely complicated landing scheme worked; for once, the reality of space exploration turned out to be just as awesome as what science fiction promised us fifty years ago. I mean, heat shields and parachutes are old hat, sure, but to follow those up by setting the one-ton rover gently on the ground using a crane suspended from a hovering rocket platform? That's just crazy talk. (Here's a nice video summary, for those just catching up.) And it worked. IT WORKED. (Sorry... I seem to have something in my eye.) Now we get to find out what remarkable science we can do.

EDIT: For those who aren't following all this on their own, a couple of followups. First, it turns out that the same (large) image by the MRO also includes the heat shield that had separated from Curiosity a minute earlier, still falling toward the ground. And second, there's already a rough video of the landing as seen from a camera on the bottom of Curiosity itself. (It sounds like they'll eventually have the whole thing in high definition, too!) This just keeps getting cooler.
steuard: (physics)
Wednesday, July 4th, 2012 11:58 am
The rumors were true! Both experiments at the LHC that were searching for the Higgs announced discovery-level evidence early this morning. This is a Big Deal, even if we did pretty much expect that the LHC would produce a result like this eventually. There's a lot to say (and lots of good discussions out there at various technical levels), but for a nice layman's overview I might recommend Bad Astronomy's Higgs post. The quotes near the beginning of this post by Tommaso Dorigo are good, too.

The very short version is this: a new particle has most definitely been discovered, and CERN found it by looking in all the places that one would look for the Higgs. Its properties aren't nailed down very well yet, but they appear to be broadly consistent with the properties we expect for the Standard Model Higgs. But, enticingly, there are tentative hints of some differences from that expectation, too. Further data over the next few years will (we hope) show us whether those differences are just random noise in the detection system or whether they reflect entirely new physics. (Most of us really, really hope it's the latter.)

Edit: I've seen some folks linking to a nice video explaining the Higgs from PhD Comics a couple of months ago. Also, since the topic of Comic Sans came up in my blog last week, I'm sad to see that the things I grumbled about last December were still a problem for the real announcement.

Edit2: Strassler's post lists a few more specifics in a nice, clean way.
steuard: (Default)
Wednesday, June 20th, 2012 10:01 pm
When our college president sent out his monthly campus update, I was pleasantly surprised to see my picture: he was happy about the very successful public viewing event that another professor and I arranged for the transit of Venus on June 5. (I'm up for tenure this fall, so the recognition is good!) We got an article on the front page of the local paper that morning, and between that and a campus email we wound up sharing the event with something like 150-200 people over the course of the evening.

It was a lot of fun. We gave people three ways to view the transit. They could stand in line to look through our good telescope (with its solar filter). (That's what's pictured above, though this was just my attempt at a hasty, imperfectly-focused shot right before I had to leave. You can barely even make out the cool sunspots in my picture.) They could look at a fairly large image projected on the wall (pictured below), which wasn't as clear but allowed lots of people to look at once. And finally, they could use my Harvey Mudd solar viewing glasses (thanks, HMC!): it was just possible to make out the round black disk of Venus blocking the sun without magnification, but that was one of the coolest parts of the experience for me.

I won't clutter up everyone's friends pages with pictures... )

That last picture shows an impromptu scale model of the inner solar system that I set up on the football field (right next to the telescopes). I put a picture of the Sun on the 25 yard line, with the right scale to match Earth right on the goal line. Venus then wound up on the 7 yard line. If you click to zoom in on this photo, you might just be able to spot the tiny picture of Earth printed there (which is also to scale, along with the Moon and the distance between them). The solar system is big, and it's something of a miracle that these tiny little planets with their differently-tilted orbits ever manage to line up enough for transits at all. In fact, I got rather excited talking about all this to the crowd: a friend took a video of me giving my last "welcome chatter" of the night, after the crowd had thinned out a lot. (The college made its own video of the event, too. But it doesn't look like anyone thought to take pictures of the long line that we had for the first hour or so.)

Finally, the fun of the event and of tracking down pictures of the sun and planets for my scale model got me interested in making a poster of the planets to put up outside our planetarium. I spent a block of time hunting around NASA websites for big chunks of a weekend and a few evenings, and assembled this:

The full-resolution PDF will print 4'x3' with a resolution of at least 120dpi (and considerably more for many objects); I'll eventually be sharing it under a Creative Commons license. I'm pretty proud of it: you can't read them on this little picture, but each planet and moon comes with some interesting fact about the object. (There are very few posters like this based on real images, and too many of those obsess over dull numerical data instead of remarkable things like Mars's seasonal dry ice caps or Triton's probable geysers of liquid nitrogen.)
steuard: (physics)
Sunday, May 20th, 2012 10:54 pm
When we realized that our trip to see family in Los Angeles was going to line up with the (partial) solar eclipse, Kim and I made sure to bring a pair of the solar viewing glasses that Harvey Mudd sent out to alumni a few weeks ago. We were on our way to dinner when it started (after showing off the baby to a bunch of thrilled relatives all afternoon), and Kim's mom and I got to watch it begin from the car. (We politely declined to pass the glasses to Kim in the driver's seat when she asked for a turn.)

When we got to dinner, it was about halfway to maximum, and we all popped outside in turns occasionally to have a look. I was just about done with dinner when it reached maximum coverage (about 85% here), so I went outside to look. It was great, and when some people nearby looked at me curiously I got all excited and showed them, too. That drew more attention, and more and more people were drawn in by all the ooohs and ahhhs. (There were even a bunch of servers and staff from the restaurant.)

All in all, I probably shared the event with two or three dozen people. It was a fantastic science outreach experience, and I think Kim and her mom mostly forgave me for abandoning them in the restaurant with the baby for 15 minutes or so. (My only disappointment was that with the sun so low in the sky, there wasn't a good view of the crescent shadows under the tree leaves: that's one of the most awesome sights during an eclipse.) I hope Alma's public viewing of the transit of Venus in a few weeks goes as well!
steuard: (physics)
Sunday, May 6th, 2012 10:30 pm
One of the things that still blows my mind about our studies of planets around other stars (beyond the simple fact that we can see them at all) is that astronomers are actually able to figure out the composition of their atmospheres. That's possible when a planet passes between us and its star: it creates a tiny shadow that dims the star's light ever so slightly, and an even tinier fraction of that light passes through the planet's atmosphere. So if the spectral pattern of the star's light changes when the planet is in the way, we can analyze the changes to tell us what's its air is made of.

We think we understand the technique pretty well, but it would be great if we could test it out on a planet whose atmosphere we already understand. If only there were some known planet expected to pass between us and its star, we could point the Hubble at it and check this calculation against the known result. Well, hey! The planet Venus is going to transit across the sun on June 5th (the next time will be in 2117: watch it (carefully), and take your kids!). Only one problem: pointing the Hubble straight at the sun would destroy its sensitive optics (much like staring at it with unprotected eyes: be careful!).

So what are they going to do instead? Point the Hubble at the moon. The idea is that studying the much weaker reflected light of the sun (and briefly, of a tiny bit of the atmosphere of Venus) will be a decent test of those models. As long as they take a careful sample of the reflected spectrum for many hours before the transit, they can get an accurate baseline reading. Then by taking equally careful (and lengthy) measurements during the transit, they can measure the difference when Venus is present. If all goes well, the measurements will yield the same "no life on this planet!" signal that we've already established by looking straight at it.

Studying Venus by staring at the moon: crazy, but awesome. (Here's the original article: Hubble to Use Moon as Mirror to See Venus Transit.)
steuard: (physics)
Tuesday, April 24th, 2012 09:19 am
I am really excited by what I've heard about Planetary Resources, a private company that has just announced plans to mine near-earth asteroids for precious metals and other resources. Here's a write-up from the Bad Astronomy blog that goes into details: it sounds like these folks have a plausible business plan (as well as the necessary level of patience, and a dedication to the underlying cause of advancing humanity in space that will be an important complement to their profit motive).

Maybe it's just too much science fiction in my youth, but I've always felt that it will be important for humanity to Get Out: to avoid having all our eggs in this one basket called Earth. There are a whole lot of reasons for that (more of them than I had as a youthful sci-fi reader), and I won't go into them now. But it's been clear to me for a long time that while governments were the obvious choice to take the first steps into the solar system, we won't really be a spacefaring species until private industry and even private individuals are able to go there on their own. Asteroid mining seems like a really good stepping stone in that direction: small and close enough to be achievable, and with enough potential profit to make it appealing to investors. As soon as one of these ventures pays off, dozens more will spring up overnight, and space industry will go from being an epic project to a commodity. I don't know if we'll ever get out of our own solar system, but I look forward to the day when we can at least use more of it than we do today.


Meanwhile, in other news (only tangentially space related), it's possible that the Fermi gamma ray telescope satellite has seen a direct hint of the long-sought dark matter particle! There's a full write-up at the Résonaances blog, but the gist is that if you look straight at the galactic core (where dark matter should be most concentrated) the telescope sees an excess of photons with a very specific energy, as if there were some unknown source at that energy on top of the known gamma ray sources (which are all spread out over a range of energies). The only model in the literature that could explain such a pattern is the decay of a dark matter particle with that same energy (or something close to it). The most likely particle mass that would explain this data is about 130 GeV: that's 130 times the mass of an entire proton (and, by an odd coincidence that might not be a coincidence, just 5 GeV or so above the current best estimate of the Higgs boson mass).

This will be a big deal if it turns out to be true: the first direct evidence of particle physics beyond the 30-year-old "standard model" (and the first concrete reason to believe that particle physics won't be dead as a practical matter after the LHC). It's thrilling stuff. The one thing that's puzzling to me about this is that I saw this news a week ago on that one blog, and I haven't heard anything else about it since. (I talked to an Alma graduate who studies experimental cosmology while he was back for graduation, and he said he'd heard about it but didn't know enough to comment beyond that.) Is there some reason for skepticism that has kept all of my other physics/astronomy blogs silent on the story thus far? Only time will tell. But it will be a lot of fun to watch.
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Saturday, February 11th, 2012 04:04 pm
My "Physics of Video Games" talk at AlmaCon went beautifully. (The con as a whole seems to be going really well, too. Thank goodness!) Many thanks to those of you who suggested ideas: some of those confirmed the value of thoughts I'd already had and others filled exactly the gaps that I had been worried about finding good examples for. My turnout was surprisingly good. I got nods of familiarity and/or understanding for lots of my "good physics" examples, loads of laughter for some of my "bad physics" examples, and some great questions and discussion when talking about using games to teach the scientific method.

In case you're curious, here's a list of videos that I used (though I often showed only a relevant clip from each). I kinda wish that I'd videotaped it!

Good physics examples:
Angry Birds (as well as some graphs of bird motion).
World of Goo (another physics puzzle game)
Dwarf Fortress (fluid flow & melting points)
Myth: The Fallen Lords (an early example of a really complete physics environment)
Skyrim (lots of cheese) (this got a laugh, but illustrated the quality of modern physics engines)

Bad (or rather, unrealistic) physics examples, that might be either good or bad for game play:
Skyrim bug with a sabertooth tiger (this had them laughing louder and louder for about a minute straight)
Resonance (flash game where jumps have no momentum)
Grand Theft Auto: San Andreas (decent laugh here; I just had a short little clip on loop)
Grand Theft Auto IV (big laugh, but as I pointed out, in many cases this behavior probably makes the game more fun)
Portal (a fictional element in an otherwise realistic game)
Portal infinite fall (what happened to conservation of energy?)
Mario 3D Land (steering during a jump)
Mario 64 (kicks in midair push you higher)

Video games teaching the scientific method (with excerpts from the full paper)
steuard: (Default)
Wednesday, August 31st, 2011 11:25 pm
Just before finals last year, I put up some workplace safety posters around our building:
(I thought about making my own, but it was hard to find good raptor art so I just went with the best existing version I could find online.) I added post-it notes denoting "21" days, then "22", then "23", and a fair number of students seemed to be amused by the whole thing. (I even admitted responsibility to a few of them.)

Flash forward to this past Monday, when I walked into the building and found these:
I have no idea who might have done it, but I was so, so proud. I can only assume it was a student (or more than one).

(Sadly, I realized today that these two posters had disappeared. My first assumption was that a housekeeping person saw the "vandalized" posters and took them down without thinking, but it struck me that it's also possible that they were taken by people who found them as funny as I do.)
steuard: (Default)
Wednesday, April 6th, 2011 12:39 pm
Man, I love teaching about electromagnetic waves. Today in intro physics I explained Faraday's law, which says that a changing magnetic field will create an electric field, which may cause current to flow around a loop. I then talked about Maxwell's realization that the opposite should also be true: a changing electric field must create a magnetic field. (It's an algebra-based intro class, so I leave out essentially all the details.) Putting those together, you realize (or at least, Maxwell did) that if the two fields can create each other then they can just travel through space on their own as a wave.

And that's where I found myself starting to literally jump up and down in excitement in class. (Well, only a little.) (Ok, I'll be honest, only a little at first.) Waves were the first topic we covered this semester, so we've come full circle. But then I showed them the speed that Maxwell derived for the waves, written in terms of the force constants for electricity and magnetism (which they've all used and measured in lab). I had students with calculators work out the resulting speed: 3.0 * 10^8 m/s. And wonderfully, in both sections, some student spoke up without any prompting and said, "Isn't that the speed of light?"

That's when I really started jumping up and down and talking rather loud. (Not just a little.) Optics was another big topic earlier this semester, and suddenly we've discovered (following Maxwell) that it's all just electromagnetism! Everything we've done really was all one topic after all! Not only do we know some methods for dealing with light, but we know why light works the way it does. I even had each class come out into the hall, form a line, and act out the part of an electromagnetic wave as they ran past a charged particle (me) and made it oscillate up and down.

It's a good class day, and I always forget how cool the topic is until I'm actually in the process of talking about it.

[And now I wonder: have I posted about this in previous years? 'Cause I totally could have. Ah well... it's cool enough to be worth saying again.]
steuard: (Default)
Sunday, March 20th, 2011 01:20 pm
LJ doesn't seem to want me to embed the video, so I'll just give a link to the original site; it's worth watching full screen.

The movie there was assembled from a huge number of still photos of Saturn taken by the Cassini probe, and it's absolutely fantastic. The best part is the full-color section, which starts a little before the one minute mark. I continue to find it amazing that we live in an era when we can actually see these sights "for real" like this... and I hope that one day, we human beings will be able to see it in person.
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Monday, January 17th, 2011 10:26 pm
[Sorry this one's a bit long, but there was a lot of great stuff on that final day.]

Friday, January 7:
Our final day at sea began with Peter Sagal leading a quiz show featuring the various entertainers. It was listed on the schedule as "Hey Hey... I'm Clever!", but after one of his comments about a pet peeve at Monday's Q&A session it was renamed "Hey Hey... I'm An Asshole!" Much like the Q&A session, this was a great chance to see a bunch of the performers a bit less formally and just cracking jokes with each other: those were some of my favorite parts of the cruise. This also may have been the only time all week that we saw David Rees's deadpan nonchalance break down into laughter. (If folks eventually get video of this online, I'll try to post the appropriate clip.)

After lunch, I ventured to the game room once again and entered the Pirate Fluxx tournament, competing for the chance to win a copy of the not-yet-released game. Sadly, Fluxx is always very random and we didn't have nearly enough time (or speed) to do lots of rounds to even that out... or at least, that's my excuse. :) While waiting for one particularly long round to finish at another table, my table played a game of "Once Upon a Time": it's a fascinating game about collaborative storytelling, but I got the sense that it could easily be prone to rules arguments and misunderstandings between players. I'd like to try it again now that I've got the gist of it. Once I was eventually bumped out of the Fluxx tournament, I played "Apples to Apples" for a while before it was time for the show.

The final evening of the cruise featured an all-request show by JoCo (we'd been turning in request cards all week), though it opened with the cruise director telling us how much he and the staff loved us. My ex-students Liana and Phil wound up sitting next to us, and as we discussed the week during intermission Liana commented that the last thing she'd expected from the trip was to find herself sitting next to her physics professor with both of us singing all the words to "I Feel Fantastic". JoCo sang lots of great songs, many of them more obscure (and many of those with more than a few stumbles along the way), and it was wonderful. There was a Fancy Pants Parade (and competition). We got a fun explanation of the underlying story for "Under the Pines", and generally lots of other great songs (including a cover of "Birdhouse In Your Soul"). Our one disappointment was that JoCo started to lead into my request ("You Ruined Everything", a favorite that Kim and I have been thinking of a lot lately), but held off because he hoped his daughter would come back from getting pizza first, and then he never got back to it. But to counterbalance that, JoCo's own request for the night was a song by John Roderick (with JoCo, Paul, and Storm as backup) called "The Commander Thinks Aloud" that was just amazing. I'll embed it below; Peter Sagal called it "[his] fav[orit]e cruise moment (among many)" (many indeed... but this is the one he tweeted about three times). All in all, this was a great final show for the week.

After that was dinner (a fancy dinner show by the staff); toward the end, one table and then more and more spontaneously got up, faced JoCo's table, and started singing "This was a triumph. I'm making a note here: HUGE SUCCESS." I helped Kim pack and fill out our comment cards, and then I went up to spend a bit of time at the farewell party on the back deck of the ship. I said goodbye to a number of people I'd met during the week, and I chatted with some famous people. I told Wil Wheaton that a friend of mine remembered meeting him when Will appeared at his dorm room to visit his roommate Dean, and Wil filled in a detail: Wil knew Dean because Dean was trying to steal away Wil's girlfriend at the time, a project in which he eventually succeeded. (Who knew?) I also expressed my admiration for Peter Sagal, and found that he did indeed remember [livejournal.com profile] ukulele from his show ("How could I forget a name like that?" he asked). After some final goodbyes and a brief attempt at stargazing, I headed off to bed.

The next morning was simple: just a final breakfast and then a wait until our turn to disembark. It was a little sad seeing all of our cruise partners scatter away, but hey, we may all get to do this again someday. (Another cruise is almost certainly in the works.)

Video evidence: I haven't seen any significant footage of the quiz show up yet: people seem to be uploading mostly in order. However, it looks like at least one person has uploaded the full request show: here's the first part (which is actually entirely Paul and Storm doing administrative stuff), but it should lead directly into later bits with actual music.

Finally, John Roderick singing "The Commander Thinks Aloud", a tribute to the astronauts who died when the space shuttle Columbia broke up on reentry. I'm tempted to embed the relevant segment of the full concert recording, since it's a bit higher quality and includes John Roderick's introduction to the song, but for now I'll stick with the music:
steuard: (Default)
Wednesday, January 12th, 2011 09:55 pm
When I first mentioned that Kim and I were going on Jonathan Coulton's Caribbean cruise, [livejournal.com profile] ukelele said "Blog or die, of course." We didn't have internet on the cruise (we were members of the Wifi Temperance Brigade), and work's been insane since we got back. But I think I've caught my breath enough to start posting brief summaries on a 10-day delay. Alas, I'd planned to take lots of pictures, but our digital camera failed the first morning and only worked sporadically later on. (I'm pretty sure these ~3000 Flickr photos are publicly viewable, though.) Despite that, it was a fantastic trip in almost every way. So on to Day 1!

Sunday, Jan. 2:
Kim and I got to Fort Lauderdale, Florida Saturday night. Sunday morning, we recognized some fellow "Sea Monkeys" while checking out of the hotel (easy enough: he had an Aperture Science T-shirt and she was wearing a USB necklace). We took the shuttle to the Holland America port together. We boarded the ms Eurodam and settled into our cabin (with its ocean view... through a lifeboat). At lunch, we played "spot the nerds": our ~380 nerds were hidden among thousands of senior citizens and vacationing families, but some of them surprised us. We registered and got our name badges and bags of goodies while admiring the geeky shirts of the people around us.

There was a Sail Away party on the back deck of the ship, where we saw JoCo and Wil Wheaton and other famous people mingling with the crowd. Once we were underway, we headed up to the opening reception for our group. After a few minutes came the first (and most surprising) Moment of Awesome: from across the room, I heard someone exclaim, "It's our Physics professor!" and suddenly two of my advanced E&M students from Claremont were running up to give me a hug (Liana and Phil, both from Pitzer). We chatted and caught up for a while, and then Kim went to change for dinner. I socialized with various people for a few more minutes and then did the same.

Our 8:00 dinner was perfectly pleasant (we shared a table with a couple more or less our age), and after it ended (around 9:30!) Kim went to bed and I went down to the tabletop gaming room for a bit. I jumped into a game of Telestrations: I'd never heard of it before, but it was a delightful cross between Pictionary and telephone. (This example captures the dynamic as the sketchbooks are passed from player to player quite well.) After that, it was time for a late night movie, which wound up being the RiffTrax version of The Happening (these are the guys who did MST3K, and two of them were on the ship). A terrible, terrible movie... so naturally they made it pretty funny. And at last, somewhere past 1am, I finally went to bed.

(Edited to add:) Video evidence: There are a few videos from the opening reception now online, including the opening comments by Paul (not Storm) and by JoCo. (Some funny bits, but mostly just setting the stage.) A video taken a few minutes later is just a crowd shot, but Kim and I can be seen standing at the bar about 5 seconds in (I'm in a grey shirt and she's wearing green that's dark and shadowed in back). More interesting(?) is a video of David Rees sharpening a pencil (no, really, and he takes it seriously: it's 8 minutes long). I'm actually right behind him in a grey T-shirt for a good bit of the video: I first show up at 2:42, and there's a glimpse of my face around 5:20. (Kim had already left by then.) Finally, here is some video of the game room, and those are my legs (in khaki slacks) and torso (in a green shirt) visible at the 15 second mark at the back left corner of the table playing Telestrations (right behind a girl named Adrienne drawing a fantastic voodoo doll).
steuard: (physics)
Wednesday, September 29th, 2010 05:20 pm
Wow oh wow. Universe Today just posted an article about an Earth-like planet discovered around a nearby red dwarf star. (The original source appears to be a UC Santa Cruz press release.)

It's right in the star's "habitable zone" (which mostly means "right temperature for liquid water") and has a mass about 3-4 times Earth's, so a quick estimate is that gravity there might be about 40% stronger than here (it wouldn't be too different than standing in an elevator as it gets going). That's plenty to hold an atmosphere. The planet has its quirks, of course: it's close to its cool sun, so a full orbit only takes about a month. Also, like our Moon it always has the same side facing "in": a planet of eternal sunlight on one side and eternal shadow on the other. Naturally, the only comfortable places to live would be in the twilight region encircling the planet between the extremes of hot and cold, where the red sun burns forever on the horizon.

This is awesome. And it's sooner than most people expected to find something like this, which may mean that planets like ours really are pretty common after all!

Now if only we could find a way to get there.
steuard: (physics)
Wednesday, March 10th, 2010 02:55 pm
Me: Great! I'm all ready for class: time to introduce magnetic fields and forces.

My Bored Brain: Wow, this looks dull.

Me: Look, it's the first day on a new subject, of course it's a bit dry. But there's some cool stuff in there.

MBB: Important, yes. But seriously: dull. I'm not gonna do it.

Me: We have to do it! I'm already behind what I'd aimed for on the syllabus.

MBB: Not gonna happen. Let's derive magnetism from scratch using electrostatics and relativity instead.

Me: Are you crazy? These guys are bound to be rusty on relativity; they may never have learned it well at all. And we don't have time for long digressions: I've dropped enough material as is.

MBB: Exactly! As the schedule stands, they're going to leave junior/senior E&M without ever hearing that electric and magnetic fields are secretly the same thing. I won't let that happen to any student of mine!

Me: Look, I just can't afford to... hold on... I can't afford... to bore them. How 'bout that.

Me, writing on board at start of class: "Today's plan: Screw it - we're doing something awesome."



Addendum: [livejournal.com profile] ukelele points out that by an awesome coincidence, today is The International Day of Awesomeness. Awesome.
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Saturday, November 8th, 2008 02:44 pm
I'm still mostly on LJ hiatus (I've got yet more job applications due next week), but I've got to share one of the rare bits of positive news from my home state: after mail-in ballots were counted, Barack Obama has won Omaha's electoral vote.

I was surprisingly obsessed with the Omaha count on election night (as Kim can attest), and I'm thrilled that one corner of Nebraska has gone on record in Obama's column. (Obama won by a decent margin in my hometown of Lincoln, too, but nowhere near enough to outweigh the rural areas that compose the rest of its congressional district.) It'll be interesting to see whether this raises interest in states splitting their electoral votes. (Omaha certainly got more attention from both campaigns this year than it would have if Nebraska's vote couldn't split.)

This makes up a little for the recent state slogan, "Nebraska: Fighting Rural Population Decline One Unwanted Child at a Time".
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Tuesday, November 4th, 2008 07:59 pm
Utúlie'n aurë! Aiya Eldalië ar Atanatári, utúlie'n aurë!
steuard: (Default)
Monday, May 12th, 2008 04:55 pm
[Despite first appearances, I promise that the humor here is reasonably accessible to non-physicists.]

The last homework assignment in my statistical mechanics class asked the students to write a computer program to simulate the simple Ising model of a ferromagnet. You model the magnetic material as an array of sites that are "spin up" and "spin down", and the simulation produces images showing how the up (black) and down (white) sites are distributed for various temperatures. Below a certain "critical temperature" the system is mostly magnetized; above that temperature, it becomes increasingly random. Especially interesting things happen right at (or very near) the critical temperature.

A couple of my students found some particularly unexpected results as the temperature approached this special value. Things went pretty much as expected as T decreased closer and closer to the critical temperature (the cluster size gets larger and larger, for example):



But when they made that last temperature change as described at the end of the page scanned above, it led to a result that I didn't expect at all:
At the 'critical temperature' T=Mr )
I've gotta say, my students can be pretty cool.
steuard: (general)
Wednesday, September 5th, 2007 10:21 am
I just finished my first lecture of the year, and I'm relieved to say that it went even better than I'd hoped. This was the first day of intro physics, so most of it was general big picture physics stuff: how physics shows up in everyday life, how it fits in with the other sciences, how the field as a whole fits together. (There was a bit of administrivia, too, but I tried to minimize that for the first day.) I probably rambled a bit, but that's par for the course for me.

But I had planned a small group activity for the very end of class that had me a little nervous. To introduce the idea of physical models, I did a brief little slide show answering the question "What shape is the Earth?" It's a sphere, of course, but that model seems laughably wrong when you're standing beneath a mountain [I used my own photo here]. And from far away in space, the Earth just looks like a point. The group activity at the end was to have the groups try to come up with other models of the Earth that might be useful in different circumstances.

My worry was that it's hard to come up with meaningful ideas on the spur of the moment (and there really wasn't a lot of time left for this at the end of class: five minutes or so). In fact, I had only come up with a couple of ideas myself ("flat", which is pretty darn good in everyday life, and "ellipsoid", which is the first correction to the basic "sphere" answer), and a student had already mentioned "elliptical" during the slide show. But as I said above, yes, you can trust the class. I think every group probably came up with "flat" (certainly the one group I called on at random did), but I also got "interlocking tectonic plates", "fractal", and "slices" (that last one being a great way to visualize the whole internal structure of the planet). That bodes well for the rest of the semester.

[And now, time to finish preparing a colloquium for Cal State Northridge this afternoon. Busy day.]