The orbit lab
Two planets share one clock. Move time forwards, compare their journeys and check a full orbit against the facts.
Ninja · Year 10Subject models, units and checks
One clock, two journeys
EarthMarsStarting point
0–1,461 Earth days. Both planets use this same time.
Reduced motion is on. Use the time controls to move between still positions.
Does one orbit take a year?
Choose a planet. Set the clock to its year length, then check whether it is back at its starting point.
- Earth year
- 365.25 Earth days
- Mars year
- 687 Earth days
Rounded reference periods: NASA Earth facts and NASA Mars facts.
Time is at zero. Move forwards by one orbital period before checking.
Position from the start
| Planet | Full orbits | Angle |
|---|
What this model leaves out
Real orbits are ellipses and orbital speed varies. Here, each planet follows a circle at constant speed. Sizes and distances are not to scale. Both start on the right for an easy comparison; these are not their actual positions on a date.
A simplified model with circular, constant-speed orbits and rounded periods. Planet sizes, distances and starting positions are illustrative. A curriculum practice example, not student work.
What the child
is learning.
Explore the learning journeyYear 10 · Subject models, units and checks
A model turns subject knowledge into something people can explore. Shared time, labelled units and a check against a reference make its behaviour testable. A smooth animation alone is not evidence that it is accurate.
Now try this…
Set time to 365.25 Earth days, then to 687. Which planet has completed a full orbit each time? Compare the other planet’s position too.