Tuesday, February 7, 2012

Winter Meeting: Tuesday Morning

Just one session in the 8 am block, then to breakfast and practicing my presentation!

It's a good one, though, a 30 minute session in the "Using the Riches of Astronomy to Teach Physics":

Using Black Holes and Extrasolar Planets to Teach Kepler's Laws (and more!)
  • They're certainly popular topics, and can help kids get into several basic physics topics
  • Kepler Mission: looking for transits around other stars using super-precise photometry
  • Neat - data shows six different planets around a single star
  • There's a Lego Orrery that they're using to simulate it (kepler.nasa.gov/education) approx. $100 cost
  • Vernier light sensor, lamp, planets, calipers (one broken bulb from clamping calipers :) ), light baffles also needed with multiple setups
  • They have TA introduce the idea - going from the data and getting students to figure out why the light dips seems a better tack
  • Questions that they have them explore: How does the % of light blocked depend on size of planet (prop. reasoning and scaling argument), orbital distance effect (you'll be getting into apparent/angular size here, which doesn't matter in the normal scale, but matters here)
  • Neat light curve from three-planet system
  • Orrery seems to not give correct orbital periods (qualitatively OK, though)
  • They have one group design for another group (and predict the resulting light curve), and the other group has to figure it out only from the data; I like that bit
  • At that point, they start getting tricky: moons, rings, off-axis transits
  • Kids like it - duh! :)  It looks fun, for sure.
  • Next activity: about the supermassive black hole at the center of the Milky Way
  • Uses data from the UCLA data on Saggitarius A
  • That's a sweet animation - I want it!
  • Students get ta plot of the paths, without context - students figure out that they're orbiting something, figuring out that it has lots of mass -> black hole
  • I guess that I'd tell kids that they're stars, then let them reason down that they're orbiting something much more massive (since that object doesn't seem to move), and get to BH that way
  • The plot is angular, so they need the distance to the galactic center (8kPc) - that might be tricky for my kids
  • We don't know the constant for ellipses in our honors class, so calculating mass would be difficult
  • The orbits are inclined, so there's that - this is getting complex quickly
  • Some student report: "We didn't think that astronomers actually had to use equations in real astronomy" - interesting: why do we teach them?  To punish the students, I guess...
  • This is recent science, and the same science that "real scientists" are working on now, rather than long-settled questions
  • Neat: you can sometimes see the little bump from reflected light as a planet's about to go behind the star - apparently, the loss of that reflection's called a secondary eclipse
  • Contact: seth.hornstein@colorado.edu

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