Date: August 19, 2011
Title: Wonders from Class, Part 2
Podcaster: Diane Turnshek
Organization: Carnegie Mellon University
Links: Diane’s website
Description: Just the good bits of astronomy class, Part 2.
Bio: Diane Turnshek is an astronomer and a science fiction author with short fiction in Analog Magazine and elsewhere. She currently teaches classes in astronomy at the University of Pittsburgh, Carnegie Mellon University and St. Vincent College. Her day job is Outreach Coordinator for the Physics Department at Carnegie Mellon University, which includes running a monthly public lecture series in astronomy, traveling to Capitol Hill for congressional visits, advising the Astronomy Club and a StuCo (a student taught course), presenting at astronomy education conferences and answering questions from the public sector.
Sponsor: This episode of 365 Days of Astronomy is sponsored by Jared Congiardo, in honor of the Orlando Skeptics, on Twitter @orlandoskeptics.
Welcome back. This is Diane Turnshek and you’re listening to Part II of “Wonders from Class,” some of my favorite parts of astronomy class. I started teaching in 1981 and, seven colleges later, I still love teaching most of the introductory astronomy material I need to cover. New methods—new materials—I’m always looking for best practices outlined in physics education studies and in astronomy teacher workshops.
Time is relative. I get such pleasure out of the questions after the relativity lecture. It’s important to first differentiate subjective time from actual time. “If you’re enjoying yourself with friends at a party, time passes quickly. That’s not what we’re talking about. That’s subjective time. One researcher threw grad students off a bridge with bungee cords strapped to their feet and goggles on their faces that had numbers flashing faster than the human eye can normally see, faster than the human brain can normally record. On the way down, the students were able to read and remember all the numbers. For them, subjective time had slowed down.”
You’ve all experienced this, right? For me, time seemed to pass excruciatingly slowly during a car accident—a slide over ice into a highway guard rail. What took about two actual seconds seemed like minutes of furious panicking. I encourage the students to think about times in their lives when time did not seem to pass at the standard rate, but either faster or slower. Doing an onerous task. Being high. Meditating. Or on a roller coaster. Once they have a label for it, it’s easier to say—that’s not what we’re talking about. This sharing sets the stage for the relativity lesson. I find that if I don’t make it clear what subjective time is first, the students think astronauts traveling at an appreciable fraction of the speed of light would just feel like they’re traveling at a slower pace, somehow. We discuss subjective time just so we can dismiss it. Some of the students have never thought deeply about the passage of time before. They take it for granted that time is a constant and passes at the same rate, one second per second, everywhere in the Universe. Block time. Absolute time. Have we not moved past Newton yet? Most of the world populace hasn’t.
“If you are near a large mass or traveling very fast, time slows down for you. An astronaut traveling quickly on the way to another star is traveling through less time than those people left behind on Earth.” I try to use the same words over and over. I hope it helps with the disbelief.
I love the mind-boggling parts the best!
Have you seen the Symphony of Science clips? They’re charming! Musicians regularly use a device called autotune to tweak the pitch of a recorded piece so that the vocals or instrumental is tuned higher or lower. Someone had the bright idea of taking Carl Sagan’s COSMOS series and autotuning it so it seems like he’s singing—cutting and pasting together sentences that seem to go together into songs. It mushroomed from there (as all good ideas should). My favorite is still “A Glorious Dawn.” It even has a stanza that is “sung” by Stephen Hawking.
“A still more glorious dawn awaits
Not a sunrise, but a galaxy rise
A morning filled with 400 billion suns
The rising of the milky way”
It’s really something. You should hear them all.
I also play the video “When Galaxies Collide” with Felicia Day, one of the Spitzer Space Telescope promotional videos. Felicia Day is geek love. Have you seen her music video “Do You Want to Date My Avatar?” She starred in the webcasts, “Dr. Horrible’s Sing-Along Blog” and “The Guild.” The Spitzer Space Telescope people have hired some fine actors—including Linda Hamilton (best known for the mom in the Terminator movies) and Dean Stockwell who I loved in “Quantum Leap.” This is what astronomy videos should look like, accurate, clever and shiny, not just talking heads. They have a whole bank of them now on different subjects at the Irrelevant Astronomy website.
Geek Dad has a comic book style video clip that you have to see! “Dark Matter Explained in Six Minutes.” I’ll include links in the show notes. One of the hardest things in teaching introductory astronomy is to limit what you say—you have to be accurate, but not get in so far that you lose people. If the really interested students want to learn more, I suggest they talk to me outside of class. The beauty of these videos is that they have just the right amount of depth that I’m looking for. Dark matter is a complex topic and yet they do such a good job you feel that you understand what it is we know about it and what it is we don’t know about it.
The students hate me for playing the Large Hadron Rap—I just have to do it though. It’s oh so scientifically accurate and mind boggling, but the tune and the terrible, terrible dancing sticks long after watching it.
Here are some things I dislike about teaching. They’re minor but annoying. A single massive star in space that goes supernova when it becomes unstable (when the core is iron ash) is called a Type II supernova. A close, double star system that goes supernova is called a Type I supernova (one large star bleeding matter onto a white dwarf that goes critical at about 1.4 solar masses). Really? One star that supernovas is a Type II and two stars? They’re a Type I? Grr.
We have Hipparchus to blame for the magnitude system. Why can’t we just change it? I know, I know. But still, smaller numbers for brighter objects, larger numbers for dimmer objects and negative numbers for really bright objects like the Sun with an apparent magnitude of -26.74. Confusing for Introductory Astronomy students.
Redshift and blueshift? The visual spectrum is Red Orange Yellow Green Blue Indigo Violet. The ROY G. BIV we all know and love. So why isn’t it redshift and violetshift? Think about it. You’d have to redshift indigo to get blue—that would shift towards the blue, but not be blueshifted.
Neap tides and spring tides? Why name them that? Spring tide has nothing to do with the spring season (any more than planetary nebula have something to do with planets). Neap tides are moderate tides when the Moon-Sun-Earth alignment is at a 90 degree angle, such as at 1st and 3rd quarter moon. Spring tides are extreme tides when the Moon, Sun, and Earth are all in a line. I tell my class to think of the extreme spring tides as, “Springing up!”
I know these are all naming conventions. I have such a problem. I need to do vocabulary with the students, but I disagree with some of the nomenclature. Identifying Population I and Population II is non-intuitive. Population I didn’t come first, they came second. Population II stars are halo populations, old, red giants with pristine abundances of hydrogen and helium. Population I stars are stars in the disk, like the Sun. Our star is laced with metals. It’s a third generation star (first there was a star that lived and died, and then another was formed from the remnants of that one, then it exploded and our Sun was formed from the left over material). So, Pop II stars came first and Pop I stars came second. How do we remember that? I get a big, yellow, foam, No. 1 hand sign and wave it around. “We’re number 1! We’re number 1!” Our star is a Population 1 star.
Metals? We call anything other than hydrogen and helium “metals.” My dad is a chemist—he has trouble with that one and also with calling stellar nucleosynthesis “nuclear burning.” “Burning” to him means “combined with oxygen.”
Whoa, when did I start ranting?
Ah, wait, I did it again! I got to the end of “times up” and I still haven’t mentioned anything about the cool class demos we do. And the labs. I run a lab a week for 15 weeks. Many of them are online where anyone can find them. I’d like to share these tried-and-true ones with you—great learning potential. Do I need a Part III? Oh, my . . . perhaps you could leave a comment on the website if you want to hear more.
Thank you for listening. This is Diane Turnshek signing off for 365 Days of Astronomy.
Symphony of Science
Behind the Scenes: When Galaxies Collide (Felicia Day, Sean Astin)
Geek Dad “Dark Matter Explained in Six Minutes”
Large Hadron Rap
End of podcast:
365 Days of Astronomy
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