This lesson is based on California's Middle School Integrated Model of NGSS.
MS-ESS1-1 Earth's Place in the Universe
PE: MS-ESS1-3 Analyze and Interpret data to determine scale properties of objects in the Solar System.
DCI: ESS1.B Earth and the Solar System - The Solar System consists of the Sun and a collection of objects including planets, their moons, and asteroids that are held in orbit around the Sun by its gravitational pull on them.
SP2: Developing and Using Models - The toilet paper is being used to mark out the correct distances in our Solar System which creates an accurate model of how far the planets are from each other.
CCC: Scale, Proportion, and Quantity - When modeling the Solar System scale is everything. Most depiction of the Solar System adjust the scale of their model to fit in a predefined space giving students the misconception that the parents are closer than they really are.
This lesson replaces student's misconception of the distances between planets. Students often believe that the planets are close to each other and an equal distance apart based on posters and models found in classrooms. These posters and models often sacrifice scale to fit all eight parents in the same frame thereby causing a misconception about the true scale of the cosmos. This activity forces the students to consider the correct scale of the Solar System by having them mark off accurately scaled distances on a roll of toilet paper.
This lesson was originally based on Elizabeth Roettger's Toilet Paper Solar System.
This activity is a companion lesson to Solar System Sentence Strip.
TIP: I ask the school's custodian if I can have have a lot of rolls of toilet paper several weeks in advance. He is able to give me several rolls a day, he just doesn't feel comfortable giving them to me all at once. I typically need ten rolls per class for five classes (50 rolls total). An alternative to that could be to ask a big box store like WalMart or Costco. I recommend you do this well in advance so that you have a back-up plan if that doesn't work.
If you ever want to see your students' heads explode, tell them that once they finish they have to roll up the toilet paper back the way you they found it.
To ease frustration it might be beneficial to have your students practice writing on a few squares of toilet paper before you begin this lesson. Students need to learn how delicate toilet paper is while at the same time how much pressure they should apply to their pens without causing tears.
They begin by labeling the first sheet of toilet paper as the Sun. The scaled distance to the planets are included in Toilet Paper Solar System Worksheet. There are two versions. The simplified version has only the average distance to each of the eight planets and is meant as a short activity.
The extended version (the one I use) has not only the average distance to each planet but also the minimum and maximum recorded distance. This show the students the eccentricity of the orbits.
For example, for the planet Mercury they have to map out Mercury's minimum distance from the Sun, Mercury's average distance from the Sun, and Mercury's maximum distance from the Sun.
An additional page includes distances to the outer objects in our solar system (Kuiper Belt objects, outer dwarf planets, Ort Cloud) and the nearest star (Proxima Centauri). I don't hand out this additional page of the extended version because the distance to the nearest star is measured in millions of toilet paper squares.
Crafting a model is not possible with the material the students have (or the time). I've included them because I deliberately want them to feel exasperated with these distance so they can appreciate the great distances that stretch out across our Solar System and our local galactic neighborhood. Don't skip this part - it conveys important information. I explain more about its meaning and purpose in my reflection.
Student Work Sample
The students had to recreate this model in their notebooks. They had to include a title, draw a portion of the Sun on the left side, attach an additional sheet of paper to their notebook, draw a straight line across their paper, and label the eight planets along this line. In order to get credit for this assignment they had to position the planets at an accurate scale distance from the Sun. At this point I'm not yet teaching the scale size of the planets.