Applying to Grad School

I haven't posted here in quite some time. I've been spending more time on my LJ and Twitter accounts (try this same username both places), and works' been pretty draining for the past year. But I wanted to post that I'm applying to return to graduate school for my PhD in either physics or astronomy, with research focusing on physics education research (PER) or astronomy education research (AER), respectively.

Noble Nobels

During WWII, two German Nobel Prize laureates (in physics) escaped to Denmark. When it too was taken over, their medals were chemically dissolved by Danish physicist Neils Bohr and Hungarian chemist George de Hevesy to keep them safe from the Nazis (and to keep the physicists safe as well, as taking gold out of Nazi Germany was a crime). The solution must have just looked like any other bottle of chemicals, because after the war was over, Hevesy precipitated the gold out of the solution, sent it back to the Swedish institution that grants the Nobels, and they generously recast the medals and reawarded them to the two physicists.

Physics Limericks

Have I mentioned I love order of magnitude estimates?

How Fermi could estimate things!
Like the well-known Olympic ten rings,
And the one-hundred states,
And weeks with ten dates,
And birds that all fly with one... wings.

--David Morin, Harvard University

There's plenty more physics limericks on Dr. Morin's webpage or in his physics textbook.

Stephen Hawking to retire

Stephen Hawking is facing a mandatory retirement clause at Cambridge University at the end of the year. But we all know that good physicists don't ever quit, they just go emeritus, stop teaching, and do research full time.

Another Pop Quiz

This one by Dr. Richard Mueller of UC Berkeley and "Physics for Future Presidents" fame, and brought to you by the NY Times. If you enter there, I'd be curious to hear your answer here as well.

Pop Quiz!

I heard someone's cellphone go off, so it's time for a pop quiz. Or if you prefer, think of it as a thought experiment. It's two questions. Answer me the best that you can, and explain your reasoning.

1) A tunnel is drilled straight through the Earth, straight from one side to the other and through the core. Let's suppose the tunnel is given strong enough walls that it doesn't collapse, and that it's well insulated so it isn't too boiling inside. A tourist sees this gigantic hole and decides "hey, there's no bottom to hit, so it's gotta be safe to jump into it," and follows word with deed. (a) Where does he end up? (b) If he could stop at the middle, what would be his weight there (as compared to his weight standing on the surface)?

2) Same tunnel through the Earth, this time you can walk along it with a barometer, reading air pressure throughout the tunnel. When you get to the center, will the air pressure be greater than that at the surface, the same, less than the surface, or entirely zero?

Magic Pen

Next time you need some procrastination, check out the "crayon physics" -style java game Magic Pen. Your goal on every level is to get a circle (or sometimes a square) to move to touch a flag. You do this via drawing simple physics-type tools. The one thing it's lacking is a pause button, that would really help.

If you ever get stuck on a level, you can skip it via the menu, but you cannot submit your "score" (number of shapes used) until you beat all levels. Once you beat all 25 levels (took me a full day of procrastination), go back and see how many different ways you can solve the same level. After a bit you'll build up a mental "toolbox" of different techniques for each level, and you can go back and see how to force a square peg into a round hole.

Help me understand a misconception....

An interesting situation came up in my Physics class today, where two of my students surprised me with a question they asked. To try and understand their thinking so I can teach the content better, I'd like to ask that everyone take a look at the below situation and tell me what you think will happen. I don't care if you know any physics or if you're a professional ear-wax taster, I want to know what you think and why.

In the picture below, Box 1 (m₁) is hanging from a string that passes over a pulley. There's no friction in the pulley, and the pulley has no mass, so it can spin freely. The string is then connected to Box 2 (m₂) sitting on a table. For simplicity, let's assume there's no friction on the table - there's some lubrication between the box and the table.



Open this page in a new window or tab to fill out the poll - there's 6 short questions (check boxes) about how the blocks will move.

X-posted a couple places.

Crayon Physics

I've been wanting a tablet PC for a while now, and this game (page currently lagging) only reinforces it. In case the page won't load, here's a review of it, and below is a demo.



I've seen tools like these accompanying textbooks before, but unfortunately never had one with a book that I chose. I should write to a few publishers to see if they have demos I can download. Unlike this "game" version, they're generally designed to accompany a Physics I course, so students can explore physical situations without friction, or so that students can perform online labs. (I'm curious about doing online labs and wish to explore the possibilities, but I will take a lot of convincing before I'm willing to do it.)

Hey baby, wanna determine the spring constant of my mattress?

Inspired by this list of physicists' pickup lines and a comment by Allison, here's a few of my own.

• Physicists are Phun!
  
• Physicists do it with simple harmonic motion.
  
• Hey baby, what's your resonance frequency?
  
• Aw man, I wanna integrate those curves of yours...
  
• Astronomers do it in the dark, under the stars, all night long.
  
• Stargazing's so cold; let's keep warm together.
  
• Bigger is better - my tube's 6" around and 2 ft long.
  

More if I come up with more - or if you add some!

On airplanes...

I keep telling people this, and they never believe me: If I'm on an airplane and the guy next to me starts talking, if I want to keep talking I tell him I'm an astronomer, and if I want to sleep I tell him I'm a physicist. Well, now I have independent proof!



Seriously, all astrophysicists discover this independently. The first time we hear someone else say it we're not at all surprised to find out that someone else came to the same conclusion on their own. It's like gravity - lots of people discovered it. I can't wait till someone comes up with So-And-So's Laws of Airplane Boredom that describe WHY. ;)

(And of course, I usually then have to go and spoil things by telling the other person that astronomy doesn't involve looking through telescopes at stars, but instead looking at computers and programming.)

I need one of these

It's a spherical cow!



At $38 and more than a foot approximately 42 centimeters in diameter, that's approxmiately 0.7¢/cm³! A total bargain!

And now some people are laughing, and other people haven't taken physics.

Scientist Badges

If scientists earned Boy Scout badges, I'd have nearly a dozen.

Vector Physics - Japanese TV style

For your entertainment, on the page I found it, it said "Vector physics in real life. From 'Trivia no Izumi' (Fountain of Trivia), the same Japanese show that figured out how heavy a fish Dora cat can carry."

For your edification, what's happening is the truck is driving forward (left) at 100km/hr, while the ball is being shot backwards (right) at (-)100km/hr relative to the truck. Note in particular the strobe effect photos of the ball shot from a stationary truck at 1:40, and the ball shot from the moving truck at 3:50. Also note that while the ball falls it drifts forward slightly, this could be due either to a mismatch in velocities or due to drafting (wind following the motion of the truck), and after it impacts the ground it bounces forward significantly, probably due to spin ("English") on the ball or possibly due to drafting (since the video is sped back up we can't tell how fast it's moving forward compared to while it was falling).

Link c/o hitchhiker.

Hawking survives Vomit Comet

That is such a relief. He did 8 of the free-fall parabolas, grinning the whole time. His motivation? Not just release from his everyday hum-drum life of a preeminent mathematician / theoretical physicist at Cambridge University, probably not even release from his wheelchair and MS, but to "encourage public interest in space". Life on Earth he says, is at risk from global warming and other threats, and "the human race has no future if it doesn't go into space."

Physics is Love

Earlier this week my students asked me if I'd cancel class on Valentine's Day. I replied of course not, because we all love physics! And to prove my point, check out this little treatise on romance as circuit diagrams. It's a little flawed as I mention elsewhere, but still entertaining and illustrates a point.