Solar System Scale and Size

Mars Space Flight Facility, Arizona State University managed by the NASA JPL Mars Exploration Program
Type Category
Instructional Materials
Lesson/Lesson Plan , Model , Activity
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



Solar System Scale and Size is a two-part activity that explores relative distances and sizes of objects in our Solar System using the 5E Instructional Model. In Activity 1, students are tasked with calculating relative distances to the Sun for the planets, Asteroid Belt and Pluto using information provided in a student handout. Once the calculations are complete, students use this information to produce a relative distance model of the Solar System with string and beads. In Activity 2, students use food items to assign relative sizes to each planet (including dwarf planet, Pluto). Please note that this evaluation only pertains to the Solar System Size and Scale 5th - 8th Grade Lesson Plan and Middle School Alignment Document.

Intended Audience

Educational Level
  • Middle School
  • Grade 6
  • Grade 8
  • Grade 7
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-ESS1-3 Analyze and interpret data to determine scale properties of objects in the solar system.

Clarification Statement: Emphasis is on the analysis of data from Earth-based instruments, space-based telescopes, and spacecraft to determine similarities and differences among solar system objects. Examples of scale properties include the sizes of an object’s layers (such as crust and atmosphere), surface features (such as volcanoes), and orbital radius. Examples of data include statistical information, drawings and photographs, and models.

Assessment Boundary: Assessment does not include recalling facts about properties of the planets and other solar system bodies.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Solar System Scale and Size deals with the portion of the Performance Expectation pertaining to orbital radius. In the first activity, students are tasked with producing a relative distance model of the Solar System. Prior to construction, students must take distance data, in the form of astronomical units, and convert it into a form that can be used to produce their model. The raw distance data used in their calculations is found in Student Worksheet C of the Student Guide. In the Farmer's Market Solar System activity, students are tasked with predicting the relative sizes of the planets using various sized fruits; however, data is not provided to aid students in their selections. Since students may resort to guessing when assigning fruits to represent the planets, teachers may wish to incorporate actual diameter data of the planets which can be easily found on the Internet. By requiring students to use data to complete the second activity, teachers will be strengthening the connection of the activity to the Performance Expectation.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
In the relative distance activity of Solar System Scale and Size, students are required to manipulate data prior to model construction. Using the results of their calculations, students measure scaled distances between objects in the solar system. Although students are not creating the model from scratch, they are required to generate the data which will be used. This last step takes the activity out of the realm of cookbook science. In the relative size activity, students are not developing their own models; rather, they are selecting which teacher provided fruits/seeds represent each planet. Since the activity does not provide any data which students can use in making their choices, the activity may be reduced to a guessing game where success is dependent on prior knowledge. To avoid this, teachers may want students to make initial selections and then refine their choices using diameter information obtained from websites or textbooks. Then, students will be able to assess the accuracy of their initial work and revise their model accordingly.

Disciplinary Core Ideas

This resource was not designed to build towards this disciplinary core idea, but can be used to build towards it using the suggestions provided below.

Comments about Including the Disciplinary Core Idea
This particular collection of activities addresses relative distances and sizes of the planets. Teachers should use this activity to introduce the idea that the size of orbital paths varies greatly in our solar system. Teachers can cover the “why” (gravitational pull) of orbital paths at a later time.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
In the first activity of this collection, students study relative distances of planets from the Sun (orbital radius) by developing a scalar model of the Solar System. One major drawback of the activity is that students use the same sized bead to represent all solar system objects. Teachers should be on the look out for any misconceptions that may result.

Resource Quality

  • Alignment to the Dimensions of the NGSS: Solar System Scale and Size strongly aligns with both the Performance Expectation and Crosscutting sections of the standard. The heart of this activity is to make a scalar model of the solar system using data which must be manipulated by the student. The compilation’s weakest alignment is in the Practices section of the standard. Students are provided with the materials to create the model and are not encouraged to develop a model on their own; however, they are required to complete the computations needed to construct the model. Teachers should note that this set of activities serves as an introduction to the core ideas outlined in MS-ESS-3. Additional materials must be used to fully address the core ideas.

  • Instructional Supports: Solar System Scale and Size is a grade appropriate activity for middle school students. The Solar System Size and Scale 5th - 8th Grade Lesson includes several differentiation tips to aid in implementation. Student worksheets to record predictions and justify choices are included but teachers may want to create additional questions that students can answer in their journals.

  • Monitoring Student Progress: The Solar System Size and Scale Middle School Alignment Document provides rubrics to monitor student achievement; however, there are no embedded formative assessments.

  • Quality of Technological Interactivity: As written, this collection lacks technological interactivity. Teachers may encourage students to use search engines to locate planet diameters in the second activity.