Science and Technology K–6 · Year 2

Earth's place in the solar system: a playground model of the planets

Earth and Space (NSW 2017); Science understanding, Earth and space sciences, and Science as a human endeavour (ACARA v9)

Practical, model not builtLow risk

This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.

The idea

Earth is one of eight planets orbiting the Sun, and the planets are not spread evenly: the four rocky planets stand within the first two and a half metres of a scale model while the four giants take up the rest of the oval.

Safety card

Low riskAn adult supervises

Hazards

Sun exposure across an outdoor lesson
The group spread over 45 m of ground, out of easy earshot
Tent pegs and witches hats as trip hazards on a playing surface

Controls

Hats and sunscreen, and the measuring done in one session of about 20 minutes
An adult stationed at the far end before anyone walks past Saturn, and a boundary agreed before the tape goes out
Pegs pushed fully down and cards counted back in at the end

Note

No chemicals and no heat. Record the activity on Primary School RiskAssess (riskassess.com.au).

What you need

A 50 m tape measure or a surveyor's wheel, and a flat outdoor space at least 46 m long (a school oval, an end-to-end basketball court, or a marked corridor of asphalt)
9 cards on tent pegs or witches hats, labelled Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
A 14 mm ball of modelling clay for the Sun at this scale, a pin to prick a 0.13 mm hole in a white card for Earth, and a 1.4 mm bead for Jupiter
A printed table of the NASA planetary fact sheet distances in millions of kilometres, with an empty column for the class's scaled distance in metres
Chalk to mark the Sun's spot and each planet's spot, and a clipboard per pair

How to do it

Stand the Sun card at one end of the measured space and chalk the spot.
Agree the scale as a class: one astronomical unit, the Sun-to-Earth distance of 149.6 million kilometres, becomes 1.50 m of playground. Fill the table by dividing each planet's distance by 149.6 and multiplying by 1.50.
Measure each distance from the Sun card with the tape and stand the planet's card there: Mercury 0.58 m, Venus 1.08 m, Earth 1.50 m, Mars 2.29 m, Jupiter 7.81 m, Saturn 14.36 m, Uranus 28.75 m, Neptune 45.27 m.
Stand one child at each card. From Neptune, look back along the line and count how many planets are inside the first 2.29 m.
Hold up the 14 mm clay Sun beside the pricked card and the 1.4 mm bead, and compare the three sizes at the same scale as the distances just measured.
Walk the line from the Sun to Neptune, counting paces, and record the count: at an infant pace of about 0.5 m the walk is about 90 paces.
Back in class, mark the eight distances on a paper strip ruled in metres and write one sentence about which planets are crowded together and which are far apart.

What you should see

The measured line comes out lopsided, and that is the finding. Computed from the NASA planetary fact sheet semi-major axes at 1.50 m per astronomical unit, the four rocky planets all stand inside the first 2.29 m (Mercury 0.58 m, Venus 1.08 m, Earth 1.50 m, Mars 2.29 m) while Jupiter is at 7.81 m, Saturn at 14.36 m, Uranus at 28.75 m and Neptune at 45.27 m. The Uranus-to-Neptune gap alone is 16.52 m, longer than the whole distance from the Sun out to Saturn, 14.36 m. At this scale the sizes all but vanish: the Sun's 1,391,400 km diameter becomes 13.95 mm of clay, Jupiter's 142,984 km becomes 1.43 mm and Earth's 12,756 km becomes 0.128 mm, a pinprick, which is why the NASA Jet Propulsion Laboratory activity has classes decide whether a model shows scale sizes or scale distances. The learner knows it worked when the measured card positions match the table to within the tape's reading and the four inner planets all fall inside the first two and a half metres.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

The planets are spread evenly, one after another, like beads on a string.
A picture of the solar system can show the planets' sizes and their distances at the same scale.
Earth sits at the centre and the Sun travels around it.
Every planet takes about a year to go once around the Sun.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science and Technology K-6 Syllabus (2017), NESA. Current syllabus; NESA's timeline is 2026 plan and prepare, 2027 start teaching the 2024 syllabus. Code read from the official syllabus document on 2026-09-22.ST1-10ES-S ST1-1WS-S
Science and Technology K-6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22.ST1-SCI-01 ST1-DAT-01
Australian Curriculum v9AC9S2U01AC9S2H01AC9S2I03AC9S2I04AC9S2I06

Sources

The pages the author read to write this activity.

All Concept Studio activities