I made you a li’l movie!

Hi! Hello. I made a small movie about a small particle accelerator.

But first. A public apology to the woman who cut my hair the other day. (And who is definitely reading this right now?) I’m sorry I made you talk about physics.

For the 100% of you who are not the lady who cut my hair, I will explain. Briefly. During a lull in standard-issue haircut conversation, Haircut Lady asked me what I did for work. My internal dialogue went like this:

  1. I should just tell her I’m a scientist and leave it at that. Supplying more information is an implicit assumption that she wants to hear me say a lot of science stuff.
  2. On the other hand, I’m going to be sitting in this chair for a long time and physics is fun to talk about.
  3. On the other hand, plenty of people have told me that they hated physics in high school and they don’t know anything about it now.  She might be one of those people.
  4. While I’m sitting here thinking, an awkward pause is stretching out into weird, uncomfortable seconds. I should just say what I do for a living.  I shouldn’t be so hung up about this.  Daniel! Have a conversation with a stranger! Go!

Anyway, so I tried a little experiment.  I told her what I do, and then I asked her what she thought of when I said “particle accelerator”. Not like a pop quiz! I wasn’t looking for a specific answer. (I said that, too.) Instead, I think scientists have a responsibility to clearly communicate their work to the general public. If the general public knows what we do, then we’re doing a good job of communicating. And if they don’t, we obviously aren’t doing a good enough job.

Your homework for tonight: What do you think of when you think about particle accelerators? What would you draw if you had to draw one? Describe it in the comments below!

Dear Haircut Lady, I’m sorry that I put you on the spot because I was curious about abstract ideas. You handled it very gracefully.

For the curious: she had the general idea that accelerators are sort of like a laser beam, but wasn’t clear on what they might be useful for. I think this is where most people are at.

Which brings me to this video I made! A colleague at work had this little science demo that she let me play with, and I had so much fun I wanted to share it.  Here we go!

DIY photo booth adventures

This is a scan of a print-out of a very handsome couple’s booth photo at our wedding. That is, this is what the final product looked like. Read on to find out more!

My cousin had a photo booth at his wedding.  It was super fun and everybody loved it and for his entire reception, there was a line of excited people outside the booth waiting for another turn.  So when we were starting to plan our wedding, I started thinking about whether I could do something similar.  Naively, it seemed to me like it should be possible to write a computer program that does all the stuff a photo booth should do.  Could I really do this myself?

“Yes” is the answer.  You can too — you can make a photo booth similar to the one my cousin used with relatively few supplies and without a lot of computer-related suffering. And everybody will love it and your party will be great!  On the other hand. If, like me, you have poor impulse control when it comes to solitary learning and technical problems, you can try to do everything yourself!  And it will only take a thousand times the sweat and effort!

Here is an uncharacteristically long post about how I built a photo booth for my wedding.  Partly, it’s a long post because it contains advice and recommendations for other people trying to build a photo booth. Partly, though, it’s long because I’m so pleased with myself.


Sitting at the metaphorical drawing board, I tried to sketch out the job I wanted my booth to do.  Here it is:

  1. The user should be presented with a very very simple setup.  Inside the booth, only the camera, a monitor (for feedback to the user), and a big shiny button should be visible.
  2. Wait for a user to sit down and get themselves situated.  Display a live image of the camera’s view in the monitor, so the user can compose the photo.
  3. The user pushes a button to initiate the photo taking/printing process.
  4. The DSLR takes 4 photos.
  5. The photos are stored on the computer with unique filenames so they’ll all be available later.
  6. The photos are stitched together into a standard-looking photo booth strip, along with a label marking the occasion and the date.
  7. Send this image to the printer.
  8. While the computer is thinking / printer is printing, the button is disabled so a rambunctious user doesn’t break the software or clog the print queue.
  9. Once the photos are printed, goto step 2.  Do this until the end of time, or until somebody digs out the laptop and presses Ctrl-C.

Also important during the planning stage was my existing inventory.  I wanted to avoid buying anything expensive or learning complicated, new software just for the sake of the booth.  Here’s the material I had on-hand before I started building:

  • DSLR camera
  • tripod
  • laptop running Ubuntu, full of free software
  • generic color printer
  • 19″ LCD monitor
  • the same Griffin PowerMate USB button that my cousin used for his booth
  • all kinds of cables and whatnot

If you look around at other photo booth DIY projects (and really, the internet is crawling with them) you’ll see that lots of people use webcams instead of DSLRs.  This isn’t a bad idea, since there’s plenty of software out there to control webcams.  Plus they’re fast and cheap.  I went with my DSLR instead since (a) I own one that takes good photos, (b) it gave me more control over photos in low-light situations, and (c) I wanted high-res photos that I could send to people afterward as keepsakes.


Here’s a thing about DIY projects: they become way less scary if you can break them down into sub-projects.  It’s not calming or instructive to tell yourself “Today I have to build a photo booth”.  By comparison, it’s fun and exciting to think “Today I need to figure out how to operate my camera from a UNIX terminal.”  Small tasks = considerably less panic.  Once I made my numbered list, each individual step didn’t seem so bad.  I finished some of those sub projects by typing a single line of code, or after five seconds of Googling.  Here, let’s walk through that list again and I’ll tell you what I did.

  1. Set everything up.  Nothing to discuss, really.
  2. Getting the camera to show a live view of the booth interior took some thought.  Fortunately, somebody had thought about it before me.  To control my camera, I used gphoto2 and a set of scripts by Alex Dumitrache called piggyphoto.  This software worked beautifully for me! And it was very, very easy to install on Ubuntu.  Once your camera is plugged in and detected by the software, you can take photos from the command line!  And do other more complicated stuff too.  Very smooth.
  3. Getting the USB button to “talk” to the computer was the hardest part of the whole process.  I don’t have much experience programming for peripheral devices, so there was a big learning curve.  Maybe there was a better solution here, but I went with gizmod, a Python-based not-really-a-daemon that looks for specific input device events and maps them to user-specified computer functions.  I wrote a script that “listens” for a USB button press, and then starts the photo taking/storing/printing process.
  4. Taking photos using command line functions was a breeze using gphoto2.  To take four photos at intervals of one second and store them on the computer’s hard drive (instead of the camera’s internal memory), do this:
    gphoto2 --capture-image-and-download --interval 1 --frames 4
  5. My friend Matt, who is smart, suggested naming each photo using the standard UNIX “date” command.  That way, each file gets a unique filename and nothing is in danger of being overwritten.
  6. You can easily stitch your photos together using ImageMagick, another wonderful bit of free software:
    montage test00.jpg test01.jpg test02.jpg test03.jpg caption.jpg -tile 1x5 -geometry +0+10 final_product.jpg
  7. Print using “lpr”.
  8. Disabling the button until the printer is finished: easy.  Just build a delay into your script.
  9. Repeat!

Since I don’t have much USB control experience, it’s totally possible that I made step #3 unnecessarily complicated.  But ultimately, gizmod was a problem.  It was heartbreaking to install and run, and then a memory leak meant that somebody had to restart the photo booth script every once in a while.  Bummer.  I’d do this part differently next time.  But anyway, it worked!  Mostly!


This part was pretty easy, actually.  I build a boothy sort of structure out of 3×6′ plywood sheets, some scrap wood I salvaged from the street, and a handful of carriage bolts.  I put it together in an afternoon.  Compared with the software, this was so easy and fun!  I didn’t have to Google anything to build it right.

I used some 1.5″ PVC pipe and connectors to build a frame I could hang some curtains from.  The curtains were just raw, unsewn fabric that was heavy enough to block out light, and that had a cute pattern for the photo backdrop.

As a side note, the plywood sheets made another fun little diversion for our guests.  We painted the plywood a flat blue before the guests started arriving, and then during a party we set out paint and brushes and our guests went to town:

Here’s the setup: camera + monitor + a big shiny button. I used some of the curtain material behind the monitor to hide the tangle of cables and the un-painted interior booth walls.


One other difficulty deserves mentioning: the printer broke.  Of course the printer broke! That’s what printers do.  Actually, it didn’t even break.  It was running low on blue ink, so it started refusing to print black and white images.  I warmly invite you to explain to me why this makes sense.  Since I had only planned on printing black and white images, I didn’t have any spare color ink at the reception.  And since printer ink is expensive, it’s not like I was going to encounter this problem during my normal testing.  Quick fix: Since all the photos were saved on the computer anyway, I just put up a note promising to email everybody their photos after the wedding.  I was disappointed that our guests couldn’t have a party favor to take home with them, but it’s better than nothing.

Aside from the software and printer problems I mentioned, I’d do one other thing differently next time: I’d add a progress bar.  I hadn’t built any user feedback into my software, so after my guests pushed the big shiny button, there were no messages saying “Say Cheese!” or “All Finished!”  That stuff would’ve added an extra layer of polish to the whole operation.  

Parting Thoughts

Do you have some DIY project kicking around in the back of your head?  And you haven’t started yet because you’re not sure whether you can do it?  I fully recommend jumping in with both feet.  Look, as long as you can do it safely and the deadline is far enough away, you can do anything you set your mind to.  If you get stuck, well, the internet is enormous and full of people who want to give you advice.  And the payoff is new skills and a really excellent sense of accomplishment.  Nothing feels quite like building something that works.

Sunrise on Haleakalā

Wedding photos: You want to see them, I want to see them, everybody wants to see them!  But oh my goodness, there are so many.  There are about 1,250 photos for us to sort through.

Sorting through our wedding photos may take a little time.

While you’re waiting, I’ll periodically post some photos from the honeymoon.  We went to Maui, because … well, because Maui.  It was totally and completely Maui.  One of the Mauiest things to do on Maui is to sit on top of a volcano at sunrise.  So we did that.  Here are some photos!

This is a crater near the summit of a probably-dormant volcano called Haleakalā, which apparently means “House of the Sun”. (Can you guess why?) The environment is so austere and lunar that the Apollo astronauts came here to train in the 1960s.

Once the sun was up, you could see all the things. All of them.

3,055 meters is apparently not enough elevation for me.

Coming up next: DIY wedding photo booth stories!

LBNL Open House

It is my pleasure to show you low-quality cell phone photos of an impossibly great physics thing.  This is a Lego scale model of the ATLAS experiment, one of the two detectors at CERN responsible for the recent discovery of the Higgs boson.

Here’s what it looks like in real life:

ATLAS Experiment © 2012 CERN

The Lego version is still pretty cool though, right?

A lot of my posts lately have been about particle accelerators and how impressive they are.  (A quick summary: particle accelerators are impressive.)  But I’ve only briefly touched on what you might want to use one for.  Let’s totally talk about that it more detail, very soon.  For now, I’ll just say that discovering fundamental properties of matter at the smallest scales requires some very very impressive, complicated machinery.  Something like 3000 people work on ATLAS.  Some of them develop hardware and maintain the various bits of the detector.  Some of them work on piping the vast amounts of collected data from the detector complex to their computing farm.  And some of them study that data, looking for evidence of new and interesting physics.  Three thousand people!  And this is only one of six detectors operating at CERN right now!

The model is color-coded, by the way. Here’s the key.

The model is built to scale. Look at those little Lego guys! Yes, the detector really is that big.

This wonderful monument of dorkitude was on display at my lab’s recent open house.  I ran a demonstration about the superconducting magnets used in certain kinds of particle accelerators, including the LHC.  I would be very happy to write a post about this, but first I need to get a few more photos together.

PS.  Should we talk specifically about the Higgs boson?  Or did you get enough of that from every other blog in the entire world?  I think it would be interesting to address your questions, if you have any.  (“What is the Higgs” is a fine sort of question to ask.)  I encourage you to post your questions in the comments section.

Book Review: “2312” by Kim Stanley Robinson

Travel! Deadlines! Wedding prep! I haven’t posted for weeks! Look, here’s a review of a book I managed to read on the plane before and after a conference:

23122312 by Kim Stanley Robinson

My rating: 5 of 5 stars

I need to use the word “transcendent” to talk about a book with spaceships in it. I am fully aware that this is a silly thing to do, and I hope that one day you can forgive me. But really, 2312 is a transcendent work of science fiction.

Let’s start with the science fiction and work our way up to the transcendence. So. Three hundred years from now (q.v. the book’s title), we’ve managed to colonize the solar system and we’ve started terraforming some likely planets, moons, and asteroids. The advent of powerful quantum computation is a real presence in this effort, and hugely extends humanity’s technological reach. And medical technology has advanced to the point where humanity has started to speciate into different variations with all kinds of weird body types and more than two genders. Oh, plus a two hundred year lifespan is starting to seem reasonable.

That’s all really rich material, and good sci fi has been written about any one of these ideas alone. But Kim Stanley Robinson takes all of these ideas together and builds something large, profound, and beautiful with them. Take the colonization of the solar system for example. This is driven by environmental catastrophe on Earth (totally understandable, given the bottomless dithering about climate change we see in 2012) and in turn it drives an expansion into new economies and systems of government. So in addition to the exciting plot and the rich emotional lives of the characters (I’m getting there, hold on) you, the reader, also get to think about twelve billion people living all over the solar system. Is 21st century American-style capitalism the natural course for all these people in all these different environments? What does the working day look like for somebody who grows up on Mercury? How would she relate to somebody who grew up on one of Saturn’s moons?

The miracle of 2312 is that it doesn’t turn into a giant essay on political science. Instead, Robinson manages to explore and develop all these ideas through strong, vital characters moving in an exciting plot. (In a science fiction novel! Imagine that!) Things kick off with Swan Er Hong, a citizen of Mercury’s only city, dealing with the unexpected death of her grandmother Alex. Alex was a politically important figure in the solar system, and this importance sucks Swan into an rich and complicated world of interplanetary politics, space travel, and quantum computers that may or may not be behaving strangely. (Get it? Quantum physics joke — you’re welcome.)

It’s worth stressing this point: Swan is a fascinating protagonist. She used to be a scientist who designed and built enormous, space-bound terraria to house animals and ecosystems that can’t survive on post-climate-change Earth anymore. But now she’s an artist, because somehow that other work wasn’t rewarding for her? She grew up on Mercury and has, yes, a mercurial temperament. And along the way she meets huge, intensely contemplative, toadlike Wahram. Wahram has a complicated past that involves manual labor but also apparently a nontrivial role in the politics of Saturn. (Wahram is a titanic, saturnine citizen of Saturn’s moon Titan. This would be trite if it wasn’t so well done.) Then, lots of things happen to them.

I want you to understand how great this is. It is a real rarity in contemporary fiction – especially genre fiction, but also in TV and movies – to find characters who are totally actualized, who speak with their own voice instead of the author’s voice, who are not just robots built to drive the machinery of the plot. Instead, each character is unique and together they interact in ways that totally make sense given this uniqueness. I guess I have high standards for books about space travel? Anyway, to sum up, I’ll just say woo-wee Kim Stanley Robinson can write!

It’s very hard for me to understand how there can be so much breadth and depth in a 550-page book. How can you have a book about interplanetary politics that is also about one person’s complicated emotional life? There are only a few other books I can think of that manage this successfully and I love them so much: Neal Stephenson’s Anathem takes breaks from the action to explore dialogues – all of them relevant to the plot, but also just intellectually cool – between a teacher and a student; Frank Herbert’s Dune starts chapters with excerpts from a scholarly work on galactic history; and of course Douglas Adams’ The Hitchhiker’s Guide to the Galaxy quotes liberally from the titular Guide. 2312 manages this in a more postmodern way, by sprinkling the book with 1-2 page “Excerpts”. It’s not explained what these passages are excerpted from, but it doesn’t matter. They’re a great way for you to catch your breath and put the action into a larger context. Some of them are long and expository, but some of them are short little political-scientific lightning strikes:

…any given economic system or historical moment is an unstable mix of past and future systems. Capitalism therefore was the combination or battleground of its residual element, feudalism, and its emergent element — what? … as feudalism is the residual on Earth, capitalism is the residual on Mars

I chewed on that one for a while before I moved on to the next chapter. Or how about this one:

It was rumored in these years that Martian spies were everywhere in the system, but that they were constantly reporting back to headquarters that there was nothing to fear — balkanization meant Mars faced nothing but a stochastic chaos of human flailing

This is what ends up making 2312 transcendent instead of just “good” or “exciting”. There’s just so much more than you could possibly expect from a single science fiction novel. It manages to look forward to a plausible, exciting future for humanity, totally, but it also somehow manages to make deeply incisive observations about the world we actually live in today, in reality. It explores wild new ways of being a human being – Swan Er Hong has given birth to a child, has also fathered a child, and has an extremely powerful computer implanted in her head – but the book still throws much of its emotional weight behind the growing, blossoming relationship between two interesting people. (Just like Jane Austen does, but different!) The action spans the solar system and multiple governments on multiple planets, but there are wildly exciting, nail-biting chapters devoted to small groups of people in difficult, exciting situations. And all the future-y technology-related stuff is cool and forward-looking while still seeming plausible.

2312 manages to be great in every way that a science fiction novel can possibly be good. Read it.

View all my reviews

Friday Physics Photos: A Scientific Conference

One of the most important things a scientist can do is to share her work with other scientists.  It gives experts the opportunity to ask critical, helpful questions; it lets scientists find areas of common interest; it gives us new perspectives on our work; and it help us to avoid stepping on each others’ toes.  You can publish your work in a scholarly journal or, if you want a more face-to-face interaction with your colleagues, you can present your work at a scientific conference.

Most areas of research have a yearly conference or two, where everybody meets to compare notes and share their most recent results.  Maybe you noticed that I wasn’t posting for a few weeks?  That’s partly because I was at the International Particle Accelerator Conference, hosted this year in New Orleans, LA.

The conferences I go to usually have two parts.  In the morning, we have a bunch of talks.

And in the afternoon, we have a poster session.

The poster session is a bit like your high school science fair.  (Yes, there really is a reason for those things!)  Everybody goes into a big room, you put up posters about your work, and then you stand around answering questions about your work.  Or, you walk around and check out everybody else’s poster.  Also, coffee.

Here's my buddy Ryan in front of his poster. Q: What's with the t-shirt? A: Scientists don't tend to wear suits. Even at conferences.

I’ve given talks and I’ve presented posters.  I actually feel like the poster session is more fun.  The people who are most interested in your research have a chance to speak with you face-to-face.  You end up having some very interesting conversations with some very interesting people.  Giving a talk is considered more high-profile, but it’s hard to have a stimulating dialogue with a dark room full of sleepy people.

I bet you’re wondering what else I got up to in New Orleans.  Well, in addition to talks and posters, the third thing to do at conferences is to have conversations.  For a week, you’re staying within a mile radius of all your field’s experts.  It’s the perfect opportunity to knock around your ideas with some smart people, to start new collaborations, and to brainstorm about the future.  I’d say I was working after hours, over dinner, just as often as I was sitting and listening to talks.

Of course, I couldn’t go to New Orleans and only work.  After talks on the last day, I ran off to the bayou with some friends and met some gators.

No, that is NOT my hand! That is the hand of a trained professional, petting a nine-foot gator.

Printing our invitations

You may have noticed that we enjoy doing things ourselves.  Especially wedding things!  Continuing with that theme, the other day we went to Reb Peters Press where we printed our wedding invitations on a letterpress.

A quick note on letterpress.  We probably could have saved some money by doing the invitations on an inkjet printer.  But (a) we felt like the wedding demanded something a little more fancy, (b) we wanted to learn something new, and (c) it was a lot of fun!  Not only is it great to get your hands dirty while making things, but printing is an excellent source of cool-sounding words that are great for high Scrabble scores; quoin and reglet are the two I can remember off the top of my head.

We desigend our invitation beforehand on the computer. We sent the design to get it photolithographically etched onto some hard plastic with an adhesive backing.

The first step is to cut the fancy invitation paper to size.  The cut has to be precise, so that you can align the paper in the press quickly and easily for a nice, straight print.  Plus, it helps to cut all the paper at once.  A cut like that calls for a special, industrial-size paper cutter.


Once the paper was cut to size, we set up the plate and mounted it into the press.










Once the plate is set up and the paper is cut, we’re ready to start printing!  First, we mixed the ink and applied it to the press.

And then it was printing time!

So we did that a bunch of times with the reddish ink for the text …

… and then we had to re-ink the press and do it all again for the accent color.

You may notice that some of the text is blurred. The cards came off the press looking beautiful. But I’ve edited the photos to protect our privacy a little bit. You’ll just have to take my word for it that the cards are legible. 🙂

Done!  We’re excited to get these in the mail!  Also, we want to give a shout-out to Rebecca Peters.  Rebecca, we had a lot of fun at your workshop!  And we’re so pleased with how our invitations came out!

Birthday Bike Bdventure!

It was my birthday the other day!  We visited the Cal Academy of Sciences with some friends.  On our bikes!  Here are some low-quality phone photos.

We accidentally biked up some of the steepest hills in San Francisco. Look at how the architecture up here doesn't make any sense at all.

Same park, looking in the other direction. We hauled my birthday cake to the top of this hill and ate most of it. I love this photo.


The Cal Academy of Sciences is one of your better science museums. Planetarium, multi-story walk-through rainforest terrarium, living roof, aquarium, ... it was full of science.


Living Roof. To me, this is very evocative of Teletubbies.


Wedding Rings!

Almost a year ago, I sneaked off and made Anaïs an engagement ring.  Since I had so much fun, and since the wedding is coming up, we went back in and made our wedding bands at the same place, Scintillant Studio, and in the same way.  Get ready for a bunch of photos!

We used recycled white gold for the rings. Here's what it looked like when we started.

I cannot say enough good things about Adam, the owner of Scintillant Studio. Not only is he smart and knowledgeable, but he's an excellent teacher as well. Thanks, Adam!

Anaïs is melting the gold with a torch. This purifies the gold, and also lets us pour it into the ingot mold.

Pouring the molten gold into the ingot mold.

The poured gold forms an ingot.

Anaïs, densifying the ingot.

Every time you do mechanical work on the gold, it gets weaker. Annealing (heating with a torch) repairs the damage and re-strengthens the gold.

Squeezing the gold between these rollers gives it its cross-sectional shape. It's called "milling".

Then we bent the rings into roughly circular shapes.

Anaïs is soldering shut the gap in Daniel's ring.

After that, there's a lot of sanding ...

... and grinding (on a rotary tool, here) ...

... and polishing.

All finished! I can't wait to wear mine.

I also want to give a shout-out to Octavia Hunter, our wedding photographer.  She took all these amazing photos and we’re very happy with her work.  Thanks, Octavia!