(EER's homepage, Astronomer's Education Notebook)
Ages: general audiences
A graphic demonstration of the varied and enormous distances in space.
Half an hour, in advance, to prepare the roll.
10-15 minutes for demonstration, plus 10 minutes or so to re-roll.
Describe the relative distances of planets from our sun. In the advanced version, describe the eccentricity of orbits in terms of the varying distance from the sun.
Starting at one end of a long hallway, unroll the toilet paper until you reach the end. Note the varying distances.
If you made the advanced version, note the variation in the orbits of Mercury, Mars, and Pluto. Note especially that Pluto is sometimes closer to the Sun than Neptune. (Pluto becomes further from the Sun than Neptune in March 1999.)
Re-roll the model to use again (repair with tape if necessary).
|Mercury - min||1.5|
|Mercury - avg||2.0|
|Mercury - max||2.4|
|Venus - min||3.6|
|Venus - avg||3.7|
|Venus - max||3.7|
|Earth - min||5.0|
|Earth - avg||5.1|
|Earth - max||5.2|
|Mars - min||7.0|
|Mars - avg||7.7|
|Mars - max||8.4|
|Asteroids - avg||14|
|Asteroids - max||22|
|Jupiter - min||25.1|
|Jupiter - avg||26.4|
|Jupiter - max||27.7|
|Saturn - min||45.7|
|Saturn - avg||48.4|
|Saturn - max||51.1|
|Uranus - min||92.7|
|Uranus - avg||97.3|
|Uranus - max||101.8|
|Neptune - min||151.1|
|Neptune - avg||152.4|
|Neptune - max||153.8|
|Pluto/Charon - min||150.0|
|Pluto/Charon - avg||200.0|
|Pluto/Charon - max||250.0|
ALTERNATIVES AND OTHER DETAILS:
Cheap, flat toilet paper generally works best.
Textured paper is okay; printed paper can be distracting.
I usually use gel or fluid pens rather than felt-tip. Pens that are very pointy or wet can tear the paper.
In the advanced version, I include the asteroid belt (the edges are approximate). I also refer to the Pluto/Charon system, rather than the planet Pluto, because the two bodies are essentially a double planet. The Kuiper Belt of comets starts approximately at Neptune's orbit. (I may someday figure out how much more paper would be needed to model the whole Kuiper Belt. Don't ask me to model the Oort Cloud of comets; it would go to about 4000 times the average distance to Pluto.)
Uranus is pronounced YOO-rah-nus. Charon can be pronounced several ways, but planetary scientists tend to pronounce it SHA-ron.
Other people have used toilet paper to make scale models of the solar system, but I did the calculations for this version using generally accepted orbital parameters.