What did you change in the model?
Labs / Astronomy
Kepler's Equal Areas
A planet is orbiting the Sun, which sits at one focus of the ellipse. Each colored slice is swept out in the same amount of time — yet the planet moves far faster near the Sun than far away. Watch the areas come out equal anyway, and read off the speed, distance, and swept area as it goes. That is Kepler's second law.
Labs / Astronomy / Kepler's Equal Areas
Kepler's Equal Areas
A planet is orbiting the Sun, which sits at one focus of the ellipse. Each colored slice is swept out in the same amount of time — yet the planet moves far faster near the Sun than far away. Watch the areas come out equal anyway, and read off the speed, distance, and swept area as it goes. That is Kepler's second law.
Why it matters
Why explore this?
Astronomy uses patterns in light and motion to explain objects we cannot touch directly. This model lets you change one part of a space system and see what the evidence would look like.
Explore
Try the model
v —r —swept —each —
Investigate
Questions to test
Predict first, try it in the model, then use what you observe to answer.
What to try
- Set the orbit to "Extreme" and pause near the Sun. How much faster is the planet at perihelion than at aphelion?
- Every wedge takes the same time to sweep — so why are the thin ones stretched long and the fat ones stubby and short?
- Compare the "swept" readout as each slice finishes. Does the area really land on the same number every time, whatever the eccentricity?
- Switch to a perfect "Circle". Does the planet still speed up and slow down, or does it glide at one constant pace?
- Change the sweep interval from T ÷ 4 to T ÷ 12. What stays the same about each slice, and what changes?
Explain
Make sense of what happened
Look for a cause-and-effect rule: what did you change, what responded, and what stayed the same? Astronomers use those patterns to infer how distant systems work.
Check
Before you leave
What visible evidence changed?
What rule could explain that change?
If you can answer all three using evidence from the model, you understand the main idea. If not, return to Explore and change one setting at a time.