Waco Gem and Mineral Club, Waco, Tx

11.1 Modeling the Solar Syatem

 

11.1: Modeling the Solar System

When I was a kid, modeling our solar system was easy. We just memorized this little ditty: My very earnest mother just served us nine pizzas. The first letter of each word represents the first letter of each planet in order from the sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. Since that simple time, we‘ve filled our solar system with an asteroid belt between Mars and Jupiter, an Ort cloud of comets surrounding our solar system along with a Kuiper belt and Centaurs, and a host of interesting moons we‘ve begun exploring via spacecraft. Plus, some scientists have kicked poor Pluto out of the family of planets, demoting it to a mere dwarf planet! Others have added a planet or two in the form of icy bodies (like Xena) even larger than Pluto that have been found in the outermost reaches of our solar system.

Work with kids to create a model of our solar system or to draw and color it on a long sheet of paper or poster board. The easiest is a model of the planets. You might choose marbles and balls of varying sizes to show how big different planets are relative to one another (from tiny, pea-sized Pluto to giant basket-ball sized Jupiter), and you might include a lamp to represent the sun. If you spread planets across a room, the heat emitted by a light bulb can illustrate how the sun‘s warmth that nurtures us on Earth makes for broiling conditions on Mercury yet barely reaches poor, maligned Pluto. You can also purchase models or posters of the solar system.

Before setting kids loose to make models or posters of the solar system, a fun activity to teach the names of our planets is via flashcards. You can make your own set by cutting planet photos from old astronomy or National Geographic magazines and pasting them to cardboard. Or, if you have a computer and color printer, you can go to web sites to download and print images of each planet onto cardstock and print or write the name of the planet on the back. Check http://pds.jpl.nasa.gov/planets/ for terrific NASA photos.

Another neat web site is Bill Arnett‘s The Nine8 Planets. This site includes a link to the International Astronomical Union‘s 2006 revised definition of a planet that demoted Pluto with this resolution: (1) A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit. (2) A dwarf planet‘ is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite. (3) All other objects, except satellites, orbiting the Sun shall be referred to collectively as Small Solar System Bodies.‘

Use Pluto as an example for talking about how we define a planet versus a moon, a dwarf planet, and small solar system bodies such as asteroids, comets, or mere celestial debris. Kids should learn that science isn‘t always fixed or definitive. Definitions change, and scientists often debate and challenge one another and don‘t always come to a consensus as new discoveries come to light.