Wednesday, February 13, 2008

Students' viewpoints on what ET might be like?

The Teaching Astronomy Blog welcomes a guest contributer: Tim Slater!

Off hand essay on engaging students to think about finding life beyond Earth...

Often when giving public talks on astrobiology and searching for extraterrestrial life, an oft posed end of lecture question is, “why are we looking for bacteria instead of for living things?” Now, I know this is a common question, so I try to make a big deal out of bacteria being alive – being organisms that take and recycle energy from their environment, alter their environment by their being there, and reproducing. I also talk about how surprising it is that bacteria can thrive in more exotic environments than humans can (aside from the jokes that thermo-philic people live just fine in both extremes of the heat of Tucson, AZ and the cold of Laramie, WY). Yet, people often ask. Perhaps it is because they’d rather NASA wasn’t spending their tax dollars on looking for “lesser” forms of life or perhaps they don’t really believe bacteria are alive – either way, it is a definite sticking point.

In pondering how to get around this while giving classroom lectures in Hilo last week, it occurred to me to try something new. I asked seventh grade students at the beginning of my classroom visit to “imagine they were an astronaut being sent to a newly discovered planet where life existed – and to creatively draw what creatures they might find there and to provide three important facts about these new life forms.” You might imagine what students drew—nearly 100% drew anthropomorphic things with arms, mouths, eyes, and legs.

So, even before I began my “lecture,” I polled students to raise their hands and how many drew something with eyes? Then I said, could several people give me examples of living things on Earth which have eyes—which many could do. Then I said, ok, could you give me some examples of living things on Earth which do NOT have eyes. It took students a few moments, but eventually, they listed trees and worms (and of course bats and sharks were mentioned too as having lousy eyesight – glad they didn’t point to my thick glasses!). I said to them, “hum, curious, I wonder if there are more living things on Earth with eyes or withOUT eyes?,” and left the question unanswered.

Then, I went through the list – examples of things on Earth with mouths, then without mouths, and then do you think there are more living things with mouths or without mouths on Earth? Followed by the same dialogue about arms and legs.

At this point, it seemed to me that many students were on the verge of considering that maybe most things on Earth don’t look like people with eyes, mouths, arms, and legs – but to be sure, I went in for the kill. I said, “well, let’s change the challenge for a moment to say, ‘imagine you are an alien from another planet sent to land on Earth and look for life…if you just landed at some random spot on Earth, would you land in the water or on land? Hum, well if you landed at some random spot on Earth, how likely do you think you could look around and see a person?” Well, to my great surprise, this didn’t seem to seal the deal as well as I thought.

So, in desperation, I grabbed an inflatable beach-ball globe of the Earth, I and started randomly tossing it to students. I said, “imagine you landed where your right thumb is, would you likely look at the window of your space craft and see a person?” And, I kept a tally on the white board of person or no person, while the students tossed the ball around to other students and yelled out the answer. Well, you know where this is going, after 15 or so tosses, when the throwing got extreme, it was clear that most of the time, a randomly landing thumb (alien space craft) didn’t hit land, let alone a population center. Now, this was the culminating piece of evidence for majority of the students – aliens might not even know there were living things with eye, mouths, arms, and legs if they visited Earth unless they were lucky. And, this, of course, supports the notion that when we go to other planets, we need to be open minded about what life there might look like and it probably doesn’t look much like us.

I hope that my luck with this continues, and that if you try this with your students, it works well too!

Clear Skies, Tim

Tim Slater, CAPER Team
University of Arizona and heading to the University of Wyoming
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