Science activity
Solar System Scale Model
Learn the planets in order! Use fruits and balls to show how some planets are big and some are small. Line them up from the Sun outward.
Materials and setup
- playdough or clay
- fruits or balls of various sizes
- paper
- markers
- ruler or measuring tape
- string
How this changes by age
Pre-K (ages 3–4)
Learn the planets in order! Use fruits and balls to show how some planets are big and some are small. Line them up from the Sun outward.
Steps
- Learn the planet names in order using a song or rhyme: 'My Very Excellent Mother Just Served Us Nachos' (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune).
- Choose fruits or balls to represent each planet by size: a watermelon for Jupiter, a blueberry for Mercury (smallest planet), a grape for Mars.
- Place a large yellow ball or balloon as the Sun.
- Line up all the planets in order from the Sun, spaced apart across the room or yard.
- Walk along your solar system and name each planet as you pass it.
- Tell a grown-up one thing that surprised you.
Learning objectives
- Name the eight planets in order from the Sun
- Understand that planets come in different sizes
- Recognize that planets are arranged in a specific order around the Sun
Kindergarten (ages 5–6)
Build a scale model of the solar system showing relative planet sizes. Use clay or playdough to make each planet the right size compared to the others.
Steps
- Learn planet size comparisons: Jupiter is the biggest (11 Earths could fit across it), Mercury is the smallest.
- Use playdough to make each planet. Start with a pea-sized Mercury, make Earth a marble, and Jupiter a tennis ball-sized sphere.
- Color each planet appropriately: red Mars, blue-green Earth, orange Jupiter with stripes, yellow Saturn with a ring.
- Add Saturn's rings using a paper plate or cardboard circle.
- Arrange your planets in order on a table and add a name label under each one.
- Share 2 facts about each planet with a family member.
- Tell a grown-up one thing that surprised you.
Learning objectives
- Compare the relative sizes of planets in the solar system
- Identify visual features of each planet like color and rings
- Communicate learned facts about the solar system
Early elementary (ages 6–8)
Build a dual scale model: one for planet sizes and one for distances. Calculate scaled sizes and distances, and research key facts about each planet.
Steps
- Research actual planet diameters and distances from the Sun. Create a data table with these values.
- Build a SIZE scale model: if Earth is a peppercorn (2mm), calculate the scaled size of each other planet (Jupiter would be about a walnut, Sun would be a beach ball).
- Build a DISTANCE scale model separately (sizes and distances cannot be shown on the same scale!): if Earth is 1 meter from the Sun, Mercury is 0.4m, Mars is 1.5m, Jupiter is 5.2m, Neptune is 30m.
- Lay out the distance model in a hallway or outside. Walk it and feel how far apart the planets really are.
- Create a planet fact card for each planet: diameter, distance from Sun, number of moons, fun fact.
- Write a paragraph explaining why you need two separate models (the distances are so enormous that the planets would be invisible specks).
- In one sentence, tell a parent or sibling what surprised you today.
Learning objectives
- Calculate scaled sizes and distances for a solar system model
- Understand why scale models require trade-offs between size and distance accuracy
- Research and present key facts about each planet in the solar system
Upper elementary (ages 8–10)
Build a mathematically accurate scale model, research planetary science in depth, and create a solar system guidebook with calculations, diagrams, and comparative analysis.
Steps
- Research detailed planetary data: diameter, mass, distance from Sun, orbital period, rotation period, number of moons, atmospheric composition, and surface conditions.
- Calculate TWO scale models, each at a different scale (sizes and distances cannot share a scale — at one shared scale either the planets are invisible specks or the distances don't fit on Earth): (1) SIZE model at 1:1 billion scale (Sun ~1.4 m, Earth ~1.3 cm, Jupiter ~14 cm, Neptune ~5 cm). Show your math. (2) DISTANCE model at 1:10 billion scale (Earth ~15 m from Sun, Mars ~23 m, Jupiter ~78 m, Neptune ~450 m). Map out where each planet would stand.
- Build the size model using clay or found objects matching your calculations. Measure each one to verify accuracy.
- Calculate additional data: How long would a road trip to each planet take at 100 km/h? How long does light take to reach each planet from the Sun?
- Compare the inner rocky planets to the outer gas giants. Create a Venn diagram or comparison chart covering: composition, size, density, moons, rings, and atmosphere.
- Create a Solar System Guidebook: include your scale calculations, planet profiles, comparison charts, and a section on recent space exploration missions (rovers, flybys, orbiters).
- In one sentence, tell a parent or sibling what surprised you today.
Learning objectives
- Apply mathematical scaling to create accurate planetary models
- Compare and contrast the properties of inner and outer planets
- Synthesize planetary science research into a comprehensive reference guide
Safety and evidence note
Read the full activity before beginning. An adult should supervise tools, heat, food, outdoor work, movement, and experiments as appropriate. Completion records that the activity was done; the child’s explanation, work sample, photo, or demonstration is stronger evidence of learning than a completion check alone.
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