How does Mars move both eastward and westward in Earth's sky? A simple interactive describes the concept of retrograde motion using both color and graphic models. Learners understand that the speed of the orbit accounts for Mars' change in direction.

Concepts

planets, planetary motion, orbiting

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Additional Tags

science

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Instructional Ideas

• Have classes create color models representing the areas of the retrograde motion of Mars
• Ask individuals to read the background information and write down key facts

Classroom Considerations

• Expects a solid understanding of planetary orbits in the solar system

• This content requires Adobe Flash to view

Pros

• Introduction gives valuable background information
• Exercises provide direction for lesson development

Cons

• None