In 2006, the International Astronomical Union defined the terms "planet" and "dwarf planet." The IAU's decision created an opportunity for students to understand the solar system better by considering the definitions of planet, dwarf planet and asteroid. New discoveries in the solar system require a change in the language used to discuss it. The activity uses direct vocabulary instruction to help students learn these new definitions.
Teacher Guide [315KB PDF file]
Student Activity [283KB PDF file]