This past week I participated, for the first time, in the annual Journey through the Universe science outreach program, which is where scientists of every stripe volunteer to go into classrooms around Hilo (and nine other places throughout the nation) and try to inspire kids with science.
This is the tenth anniversary of the program, and living in Hilo for the past several years I was vaguely aware of its presence, but this is the first time I participated. Each presenter is given a choice as to how they want to participate: what days they're free, what grades they're interested in speaking to, etc. These are then coordinated by Gemini Observatory with the various schools to match people to what they selected.
I elected for younger children and ended up with five classes of 2nd-graders to visit. For my subject I decided to talk about the scale of outer space (a topic that I greatly enjoy and find very mind-stimulating), and specifically the scale of our solar system (a subject a little more familiar at that age). For that I used a simple model, put together in the following manner.
When measuring distances in the solar system, astronomer often find it convenient to use the Astronomical Unit, or AU. This actually has a very specific definition, but for all intents and purposes it can be thought of as the average distance between the earth and the sun. Earth, by definition, is 1 AU from the sun; Mercury and Venus are less than a single AU from the sun, while the other planets are more than 1 AU, all the way out to Neptune at an average distance of 30 AU.
For the model I used, I equated one sheet of letter paper to one AU, then taped 30 sheets of paper together to represent the distance out to Neptune. I then stuck pictures of the planets at the appropriate distances along the model (sizes not to scale, but at that scale they'd have been invisible). For the pictures I printed out a bunch of black-and-white pictures of the planets meant to be colored in and had the kids do the coloring (saving me work, and giving them something to do to fill up time and keep their attention. It turned out to be much more popular than I had expected).
After the first two runs where I ironed out a few bugs, it went quite well for the remaining three classes. It was a bit nerve-wracking, I must admit. I've been public speaking for over ten years, and giving a talk in front of an attentive audience doesn't faze me, whether it's a prepared talk or extemporaneous. But it's a little harder to maintain composure and flow when the audience is quite comfortable with expressing its own opinions or interjecting its own comments from time to time. Apparently I was interesting enough that they were too absorbed to interrupt most of the time, and I always ended with ten to fifteen minutes of question-and-answer, so that probably helped. It was really gratifying to see the majority of the kids asking questions rather than just a few.
Overall it was a very interesting experience. A little nerve-wracking and a little stressful beforehand, but quite exhilarating to see the looks on kids' faces when they realized that Neptune is really, really, far out there. I got some very nice comments from the teachers of the various classes and the kids seemed to really enjoy it as well. I don't know if I'll do it again, but I'm certainly glad I got the chance to do it this time.
(If anyone wants to make their own solar system model, the average distances to the planet in AU are 0.4, 0.7, 1, 1.5, 5.2, 9.5, 19.2, and 30 for Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, respectively.)