It could be that the poor drawings Tina sees are the result of students not
understanding scale drawings, but I doubt it. I'll side with Tina on this,
and I'll say I don't think students have anywhere near the correct mental
image of the relative sizes of things.
When I teach astronomy, one class project is to make a scale solar system.
I'm sure others have done this as well. We go out to a field and put
to-scale planets on sticks, then space them out with the proper separation.
Sometimes we try to locate them in the proper orbital positions, other times
we just pretend they're strung out in a line. We put a telescope at earth's
position and try to see our model planets through the telescope. Depending
on the scale we choose, the outer planets typically have to be placed
alongside the road because we might be driving a couple miles before we
place Pluto.
This is hard to do with anything but a fairly small class... but if there is
any way to pull it off, you've got to do it. Students are simply astounded
by this. Some actually argue for several days that we must have messed up
the calculations. If the planets are roughly the sizes of marbles, nearly
100% of the students are convinced we could construct the model on the top
of a lab bench. A few who realize it's bigger than that are still sure we
could do it in the gymnasium. The idea that a football field isn't big
enough never crosses their minds.
It's also interesting to see their reaction to the fact that they know
exactly where we put Pluto, because we drove, or rode bikes, or walked
there... yet when we get back to earth and look for Pluto with the
telescope, we can't find it.
A few students never believe it even after doing this. But I actually have
had some students who, at the point of realizing what we're observing,
simply can't stand. They actually sit down on the ground and stare at it,
perhaps commenting something like "this is simply incredible."
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817