Modeling the Solar System

Active learning works for modeling the solar system because students need to physically engage with scale to confront the vast emptiness of space and the relative sizes of planets. Moving beyond flat diagrams forces learners to confront proportions they would otherwise dismiss as abstract numbers.

• Grade 6
• Science
• 4 activities
• 35 min–50 min

Learning Objectives

1. Calculate appropriate scales for representing planetary distances and sizes based on provided astronomical data.
2. Design and construct a physical model of the solar system that accurately reflects relative sizes and distances.
3. Evaluate the limitations and inaccuracies of common solar system models, identifying specific distortions.
4. Compare and contrast the relative sizes of the Sun and planets using scaled measurements.
5. Explain the challenges encountered when attempting to create a truly representative scale model of the solar system.

Project-Based Learning

⏱ 45 min·Small Groups

Schoolyard Walk: Linear Scale Model

Choose a scale where the Sun is a basketball at one end of the field. Calculate and mark planet positions with cones or balls based on average distances. Students walk the path in groups, measuring steps between planets and noting the vast gaps. Conclude with a class chart comparing model to real data.

Prepare & details

Design a scale model that accurately represents the vastness of space.

Facilitation Tip: During the Schoolyard Walk, walk backward from the Sun so students can see how far back they need to place Mercury, creating a sense of the scale before they measure.

Setup: Flexible workspace with access to materials and technology

Materials: Project brief with driving question, Planning template and timeline, Rubric with milestones, Presentation materials

• Apply
• Analyze
• Evaluate
• Create
• Self-Management
• Relationship Skills
• Decision-Making

Project-Based Learning

⏱ 35 min·Pairs

Pairs Blueprint: 2D Scale Drawing

Pairs use planetary data to calculate diameters and distances on graph paper, drawing the solar system to scale on a long roll of butcher paper. Label sizes and orbits accurately. Pairs present their drawings, explaining scale choices and limitations.

Prepare & details

Evaluate the challenges of creating an accurate scale model of the solar system.

Facilitation Tip: For the Pairs Blueprint, provide grid paper and colored pencils, and ask students to label each planet with its scaled diameter in millimeters.

Setup: Flexible workspace with access to materials and technology

Materials: Project brief with driving question, Planning template and timeline, Rubric with milestones, Presentation materials

• Apply
• Analyze
• Evaluate
• Create
• Self-Management
• Relationship Skills
• Decision-Making

Project-Based Learning

⏱ 50 min·Small Groups

Small Groups Build: Hanging Mobile

Groups paint and size foam balls for planets relative to a central Sun ornament. Attach with strings scaled to orbital distances, balancing the mobile. Test by spinning gently to simulate orbits, then critique scale accuracy in group shares.

Prepare & details

Critique common misconceptions about the relative sizes and distances of planets.

Facilitation Tip: When students Build a Hanging Mobile, have them hang the Sun first, then measure and adjust the strings for each planet to maintain scale.

Setup: Flexible workspace with access to materials and technology

Materials: Project brief with driving question, Planning template and timeline, Rubric with milestones, Presentation materials

• Apply
• Analyze
• Evaluate
• Create
• Self-Management
• Relationship Skills
• Decision-Making

Project-Based Learning

⏱ 40 min·Whole Class

Whole Class Simulation: Human Solar System

Assign students roles as Sun and planets. Position them to scale across the gym or field using measured tapes. Rotate students to show orbits, discussing feelings of distance. Record observations on a shared digital map.

Prepare & details

Design a scale model that accurately represents the vastness of space.

Facilitation Tip: In the Human Solar System simulation, assign students to hold signs with planet names while others measure distances with a trundle wheel to ensure accuracy.

Setup: Flexible workspace with access to materials and technology

Materials: Project brief with driving question, Planning template and timeline, Rubric with milestones, Presentation materials

• Apply
• Analyze
• Evaluate
• Create
• Self-Management
• Relationship Skills
• Decision-Making

Teaching This Topic

Teachers should begin with a quick data dump of planetary diameters and distances, then let students struggle with scale choices before offering guidance. Avoid giving them the 'correct' scale; instead, let them recalibrate after measuring their first attempt. Research shows that students who revise their models based on measurement data retain spatial understanding better than those who follow pre-set instructions.

What to Expect

Successful learning looks like students creating models where planet distances and sizes match scaled data, discussing why some scale choices don't fit in classrooms, and using measurements to justify their model designs. Students should express surprise at how empty space is compared to textbook images.

Watch Out for These Misconceptions

Common Misconception

During the Schoolyard Walk, watch for students placing planets in tight clusters or assuming inner planets are similar in size to outer planets.

What to Teach Instead

Have students use the 1-meter Sun as a reference to measure each planet's scaled diameter with a ruler, then place the planets at their calculated distances. Ask them why their initial placements don't match the data.

Common Misconception

During the Pairs Blueprint, watch for students drawing planets as equally spaced circles regardless of data.

What to Teach Instead

Require students to calculate each planet's scaled diameter in millimeters and label it on their drawing. Then, have them measure and mark distances from the Sun using a ruler, forcing a comparison between size and distance.

Common Misconception

During the Small Groups Build, watch for students making the Sun only slightly larger than Jupiter.

What to Teach Instead

Provide a 10 cm ball for the Sun and challenge students to scale Jupiter proportionally. When they struggle, ask them to measure the ball's diameter and compare it to the diameter of a pea for Earth, then adjust the mobile accordingly.

Assessment Ideas

Peer Assessment

After the Hanging Mobile activity, students present their models to a small group. Peers use a checklist to evaluate: Is the scale factor clearly stated? Are the relative sizes of at least three objects represented proportionally? Are the relative distances between at least two objects shown to scale? Peers provide one suggestion for improving accuracy.

Quick Check

During the Pairs Blueprint activity, provide students with a table of planet diameters and distances from the Sun. Ask them to calculate the scaled diameter of Jupiter and the scaled distance of Mars from the Sun, using a Sun diameter of 10 cm. Collect and review calculations for accuracy.

Exit Ticket

After the Schoolyard Walk, students write down one common misconception about the solar system's scale (e.g., planets are close together) and explain how their walk helped to correct this misconception.

Extensions & Scaffolding

• Challenge fast finishers to add the asteroid belt and Kuiper belt objects to their scale models, researching their sizes and distances.
• Scaffolding for students who struggle includes providing pre-calculated scale distances on cards they can place first before measuring.
• Deeper exploration involves researching how spacecraft travel times to planets change when using scaled distances, connecting math to real missions.

Key Vocabulary

Astronomical Unit (AU)	A unit of measurement equal to the average distance between the Earth and the Sun, used to measure distances within the solar system.
Scale Factor	The ratio between a measurement on a model and the corresponding measurement on the actual object, crucial for proportional representation.
Relative Size	The comparison of the physical dimensions of celestial bodies to each other, showing how much larger or smaller one is compared to another.
Orbital Distance	The average distance of a planet from the Sun along its elliptical path, a key factor in determining the vastness of the solar system.