Category: astro 101

What do you mean by that, again?

Oh sure, trust me to turn a fun Twitter #hashtag into a posting about education. Well, sorry, I filter everything I read and experience through my education filter (or my will-my-kids-have-a-meltdown? filter).

I’ve been reading my tweeps #tweetmy16yearoldself messages on Twitter, thinking to myself, Geez, that kid was way more with it than I was. Like my #spacetweep friend @Zarquil, who tweeted

#TweetYour16YearOldSelf Honestly, you’ve got it all figured out already. Listen to your own heart and don’t put so much reliance on others.

Or my math teacher friend @ptruchon who wrote to himself,

Thanks for spending so much awesome time learning the guitar. I wouldn’t have time now, and I’m still enjoying it. #tweetyour16yearoldself

And then my education friend @janniaragon tweeted something that I’m paraphrasing from memory because the tweet was a couple of days ago and it’s slipped off the timeline.

“slim-leg jeans, black hair with bangs, t-shirt from [somebody’s] concert”

You see, @ptruchon and @Zarquil are tweeting TO their 16 year-old selves, sending a wise message back in time. But @janniaragon is tweeting ABOUT her 16 year-old self, a 140-character snapshot of herself back then. That’s the way I interpreted #tweetyour16yearoldself and I’m wasn’t keen to recall and share those awkward years.

Different people have completely different interpretations of the word “tweetyour16yearoldself”, producing completely different responses. Just like I see in undergraduate physics and astronomy classes every day! The instructor says an important word which sits, in his or her mind, at the pinnacle (or is that “apex”, @ptruchon?) of a pyramid of background knowledge and concepts. But the students interpret the word in a different way and attach none of the background the instructor assumes is there. Or worse yet, attach a different background and then struggle to hang the instructor’s version of the concept on scaffolding that isn’t there.

The biggest offender in my field is “theory”. To astronomers, physicists, scientists in general, “theory” is the pinnacle of science. Why, if you produce even one outstanding theory in your career, you’ve made a valuable contribution to the field. But to students, “theory” is often a vague guess, a stab-in-the-dark. Actually, let me quote from a new astronomy textbook, “Investigating Astronomy – A Conceptual View of the Universe” (W.H. Freeman and Co, coming soon) by @caperteam and @rogerfreedman. They say it much better than I can:

In everyday language the word “theory” is often used to mean an idea that looks good on paper, but has little to do with reality. In science, however, a good theory is one that explains reality and that can be applied to explain new observations.

It’s all about interpretation. Instructors, be sure to share the pyramid of background knowledge behind key words when you use them. And students, interrupt your instructor and ask, “What do you mean by that, again?”

The birth of a clicker question

It’s easy to come up with poor clicker questions, ones that merely test who has memorized X, Y, or Z from the previous slide. Or questions where there is no way to figure out the answer: either you’ve got it or you don’t.

Good clicker questions, on the other hand, take some time to create. Sure, you might stumble onto a good one every now and then, and it gets easier as you do it more. But it’s really gratifying when you put in the time, and it works. Here’s my story.

The constellation Orion
The constellation Orion(APOD 2008 October 15)

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Interpreting formulas and graphs

When you pose a question to students about a non-trivial concept, and they get it wrong, it’s not obvious where the error occurred, which step they missed or misunderstood.

Every now and then, though, you find a “diagnostic” question that clearly discriminates between the people who have a certain morsel of knowledge and those who don’t. I found one of these questions in the #astro101 class I’m working on.

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