The teaching theme this week is the solar system. While I'm reasonably good with the mechanics of the system, way back when I learned about it (approximately the Jurassic era), things were quite different. For one thing, Pluto was still a planet. So I'm taking some time in this little blog and organizing notes and comments about the planet and some exercises I can do with the class.
Since I have a fairly difficult class (k-2nd grade... which means some of them can read, only one can tie knots, one has ADHD, all have short attention spans) and a fairly challenging class (interested in science, grades 4-5, most have parents who read or are in the tech field) I'm going to look up science activities and factoids for the classes. Some of the factoids I don't have to memorize, since their take-home is a puzzle cube that can be rotated to form pictures of the planets (along with facts about the planets.) This isn't a problem for the older group, but my younger group won't be able to make the cubes for a variety of reasons and many of them won't be able to read the information.
So what makes a planet? It has to have enough gravity to pull it into a round shape, it has to be orbiting the sun (not another planet) and has to have "cleared its orbital path" of other objects. Everything else is something else.
Take "Plutoids," for instance. We have four: Pluto, Eris (formerly known as "Xena"), Makemake, and Haumea. However, there are other celestial objects which meets almost all those requirements but aren't "Plutoids". These include Quaoar, Sedna, (once hailed as the 10th planet), the "asteroid", Ceres, and a newly discovered body called "Orchis." Large enough that it has a rounded shape, it is now classified as a "dwarf planet."
The others are also classified as "Plutinos", a very new classification of Kuyper Body Objects -- objects that orbit twice for every three orbits of Neptunes. And then there's "Centauroids." But explaining this to a pack of elementary school students is going to be mind numbingly dull and terribly complex, so telling them that these are "in an asteroid belt far away beyond Neptune" is the best solution.
So, a game of "how far away is everything" is in order.
Millions of Miles from the Sun:
30.........................Mercury
60.........................Venus
90.........................Earth
140.......................Mars
480......................Jupiter
880......................Saturn
1780....................Uranus
2790....................Neptune
3660....................Pluto
Sedna is three times further away than Pluto!
