IMPACTS AND EXTINCTIONS -- AN 8th GRADE EARTH SCIENCE UNIT

No other geologic process has the ability to shape a planet’s surface like the impressive and destructive force of a meteorite impact. Although the cratering process is not commonly covered in middle school curricula, impact cratering provides an exciting and engaging means for students think critically about many aspects of the Earth System. From the formation of the Earth to the extinction of the dinosaurs, impact events have had profound consequences on the history of the Earth and life, in the present, past and future. Using the historical impact cratering record of the Earth and Moon, a 10 day Earth Science unit titled “Impacts and Extinctions” has been created to teach students about impact events and their subsequent effects on life on Earth. This unit will be covered in three parts: an introductory impact cratering lab, a computer modeling activity exploring the geologic effects of impacts, and a K/T boundary discovery activity.

Using inquiry-based teaching methods and the “5 Es Learning Cycle”, students will use common target and projectile materials to make their own craters in a laboratory activity. They will explore the effects of different projectiles and target materials, and vary the speed and impact angle of the projectiles. Students will plan their own experiment to examine these variables, collect and graph their data, and analyze how these variables affect the resulting crater. Using online computer models, the students will explore the primary effects of an impact event including the resulting tsunami, air blast, and seismicity. Students will also explore the biologic and geologic effects of the notorious Chicxulub impact that played a role in the extinction of the dinosaurs and over 50% of genera. To close out the unit, the students will use what they have learned to hypothesize about the effects a meteorite, similar to the one that ended the reign of the dinosaurs, would have on today’s Earth.

This lesson plan has been designed for the 8^th grade level but can be tailored for different age levels. For example, the Geoscience department will incorporate these materials into current Astronomy and other lab courses and use them in their geoscience education outreach program. The materials will be made available for area teachers to borrow and use in their classrooms.