Brief Description: This two-part activity, adapted from (Foley, 1992) and (AMATYC, 1995) respectively, gives students the gravity, period and distance data shown in the table below and asks them to: (1) simulate the paths of objects freefalling from 500 meters above the surface of each planet, and (2) plot the approximate average distance from the sun versus the period for each planet and use their graphing calculators to derive Kepler's Third Law.

Mathematics Topics: This activity involves vertical motion, quadratic equations, parametric equations, power functions, and regression equations.

Mathematical Thinking: Students derive equations, make predictions, visually and algebraically analyze data and equations.

Technology: Graphing calculators are used to graph parametric equations, label and trace graphs, and calculate regression curves.

Sample Screen Shots:
Below are screenshots showing freefall and the relationship between period and average distance from the sun.

Figure 1. Equations and graphs simulating freefall motion

Figure 2. Scatterplot, regression equation, and regression graph illustrating Kepler's Third Law