In this activity, learners build a scale model of the solar system using a roll of toilet paper. There are two separate handout versions included for making either a 200-sheet model (85 feet) or a 100-sheet model (42 feet). The instructions suggest using gel pens on cheap, flat toilet paper to mark the name and location of the sun, the planets, and Ceres (to represent the asteroid belt). The background information includes limits of this model: these are average distances since planetary orbits are elliptical, and the planets will never actually be in a straight line like they are here. There is also a math scaling extension.