Learning Objective: This activity forces students to look for relationships between different characteristics of the planets and to explain these relationships.

Specific Science Content Standards

• Earth in the solar system
• Origin and evolution of the solar system

• Understand Measurable Attributes Analyze Characteristics Make Predictions Based on Data
• Make Connections

Space Update: Solar System

Introducing the activity:
Tell students that the planet on which they live determines their age and their weight. Both of these quantities will change as people travel to the different planets. Explain that students are going to record data about each planet and then use these data to compare the planets. Ask all students (individually or in groups) to fill in the table first (except for the last column). Then work through the problems together as a class or in groups. Encourage students to describe their findings each step of the way.

Extending the activity:
The surface gravity and density activities are the most difficult. Surface gravity depends on the mass of the planet and inversely on the square of the planet's radius. This may be difficult for students to predict, but if they graph surface gravity vs. mass or surface gravity vs. radius, the relationship will be apparent. High school students can plot in log-log format and discuss exponents. In calculating density, students may have difficulty with the units.