I went back to school today at the Wehr Nature Center for volunteer teacher training, and I finally figured out how the moon’s phases and eclipses are produced. It took a hands-on experiment with a classroom of adults to finally get the concept across. There was a bare light-bulb illuminated on a stand. We all stood around in a circle, facing it. Then we were each handed a four-inch Styrofoam ball on a stick. This represented the moon. We were the earth. Placing the ball in front of us at arm’s length to block out the light from the bulb, we got the concept of a solar eclipse. Moving the ball slightly so that the shadow no longer fell on our faces symbolizes the new moon. Taking the “mooncicle” in an orbit to our left, we watched the crescent of light appear and grow larger until it reached the quarter moon position at a 90 degree angle. Then, we circled it around until we were between the “moon” and the “sun”. Our shadow cast on the moon is a lunar eclipse. Eclipses don’t happen every month, because the moon’s orbit isn’t in synch like that. Crescent on the left is waxing, crescent on the right is waning . Got it. Then our naturalist asked us, “Does the moon rotate?” Um. Well, there’s a dark side of the moon that we never see, so….no? Wrong. If the moon didn’t rotate, we’d see the dark side eventually. Because the moon rotates just once every month, we always see its face. Huh? It wasn’t until two volunteers did a “do-Si-doe” maneuver and then an earth-facing cycle that I realized that the moon rotates in order to always face the earth. Ah, the light dawns!!
Then we did an experiment that proved to me that learning about astronomy from a 2-dimensional textbook was not helpful! We partnered up. One person got a 4-inch ball for the earth. One got a pom-pom sized ball for the moon. We were asked to hold those objects at the distance we figured would represent a scale model of the actual distance the moon is away from the earth. I eye-balled it at about 12 inches. That’s what I remember from illustrations and posters. We were then handed a piece of string that had been measure to the real scale. I took my end and began walking. I ended up 10 feet away. In order to put that scale into a textbook, the dot for the moon would be too small for most kids to see.
Here’s another little blip of information that I discovered. During the month of August, my birth month, the predominant constellation visible in the southern sky is called Aquila. Aquila means “eagle” and according to mythology, he was a pet of Jupiter and did many tasks for him (like continually attacking Prometheus while he was bound to a mountain side). There is also a character in the Bible named Aquila. He was the husband of Priscilla. I wonder if my parents were aware of this ancient coincidence when they named their August girl Priscilla?
I could barely wait to get home and tell Steve what I learned. I love school!