Read the AU ruler
One AU is approximately the average distance from Earth to the Sun.
Solar System Scale Trip
Travel along a linear astronomical unit ruler and compare planet diameters on a separate size ruler.
Grades 3–5 · Earth Science
Your goal
Select Earth and travel to its average distance from the Sun. Read the AU label, then compare its diameter on the separate size ruler.
Reduced motion is on. The controls still update the scene.
Traveler at 0.00 AU. Earth averages 1 AU from the Sun and has 1 Earth diameters.
AU
The distance ruler uses rounded average orbital distances, all on one straight line for comparison. The separate diameter ruler uses a different linear scale. Dots on the distance ruler are enlarged location markers. This is a scale map, with no travel time or planet motion.
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Learn with Solar System Scale Trip
Solar System Scale Trip helps elementary learners explore how widely the planets are spaced. Select a planet and move the traveler along a linear ruler measured in astronomical units. Compare the crowded inner planets with the long gaps between the outer planets, then read the selected world’s average distance from the Sun. A separate diameter ruler shows how large each planet is relative to Earth. Keeping size and distance on different labeled scales makes both comparisons readable without pretending that the picture is a realistic snapshot of planetary positions.
What to look for
Look near the Sun
The inner planets cluster together when every AU takes the same amount of space.
Use two scales
Compare diameters on the lower ruler rather than the enlarged location dots.
For teachers and curious learners
Distinguish average planetary distances from planetary sizes using independent linear scales. Ask students to predict what will happen, change one setting, and explain what they observe. Learn gives a starting point. Practice and Challenge offer new goals with the same scene.
Rounded average Sun distances and approximate diameters. Planets are lined up for comparison; distance markers, diameter ruler and traveler icon use explicitly different scales. No travel time is modeled.