Physics · Interactive learning companion

Kepler's Laws of Planetary Motion

Distinguish orbital shape, equal-area sweeping and the period–size relationship.

Landscape activity · use fullscreen on a phone for larger controls

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📝 Description

Kepler's Laws of Planetary Motion is a visual simulation for studying orbital motion. Students explore elliptical orbits, changing speed, and the relationship between orbital period and distance. It supports astronomy, physics, and mathematics learning.

📋 Instructions

Start the simulation and observe planetary motion. Adjust available values where provided and compare the orbit with Kepler's three laws.

🎓 Learning Guide: Kepler's Laws of Planetary Motion

Learning focus: Distinguish orbital shape, equal-area sweeping and the period–size relationship.

Physics Interactive learning companion

Learning objectives

State Kepler’s first, second and third laws with their assumptions.
Connect faster motion near perihelion with conservation of angular momentum.

Concepts and principles

An ideal two-body bound orbit is an ellipse with the central body at one focus.
The line from planet to star sweeps equal areas in equal times.
For orbits about the same central mass under Newtonian gravity, T²∝a³.

Examples and worked solutions

Planet B orbits the same star with semimajor axis 4 times Planet A’s. What is T_B/T_A?: Worked solution: 4^(3/2)=8.

Try this activity

Look for a noncircular orbit and the focus, rather than assuming the star lies at the ellipse centre.
If orbit position can be controlled, compare motion near perihelion and aphelion.
Treat display times or angles as illustrative until the model’s numerical behavior is checked.

Expected observations and explanations

A planet travels faster at smaller orbital radius in an elliptic Kepler orbit.

Assessment questions and answers

Does equal-area sweeping mean the speed is constant throughout an ellipse?: Answer: No; orbital speed varies so that area rate stays constant.