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Classroom Resource
Chemical Signatures of Asteroid Impacts

Summary

A lesson in which students analyze the chemical data that led researchers to conclude that the K-T boundary layer contained an extraordinary concentration of iridium. 

Appropriate for: high school physics, chemistry, and earth science (all levels)

This lesson serves as an extension to the Howard Hughes Medical Institute short film The Day the Mesozoic Died. The film identifies the presence of high quantities of iridium (Ir) in the clay layer at the K-T boundary as a key piece of evidence of the asteroid impact hypothesis. In this lesson, students will calculate the chemical signatures of two K-T boundary samples and compare them to those of a chondrite—a rock that originated from space—and a typical basalt—a rock that originated from Earth’s mantle. Students then evaluate the data to determine how well the evidence supports the conclusion that the iridium signal in K-T sediments was produced by an extraterrestrial impact.


Curriculum Connections:

NGSS (April 2013)
HS-PS1.A, HS-ESS1.B, HS-ESS1.C, HS-ESS2-2, HS-ESS2.A

Common Core (2010)
CCSS.Mathematics.MP.4, CCSS.Mathematics.MP.2, CCSS.ELA-Literacy. RST.9-10.7, CCSS.ELA-Literacy. RST.11-12.7 CCSS.ELA-Literacy.WHST.9-12.1, CCSS.ELA-Literacy.WHST.9-12.2 


Supporting Materials (10)

Short Film
The disappearance of the dinosaurs at the end of the Cretaceous period posed one of the greatest, long-standing scientific mysteries. This three-act film tells the story of the extraordinary detective work that solved it. 
Film Guides
The following classroom-ready resources complement The Day the Mesozoic Died, which tells the story of the extraordinary detective work that led to the stunning discovery that an asteroid struck Earth 66 million years ago, triggering a mass extinction of animals, plants and even microorganisms.
Classroom Resource
A lesson in which students analyze graphs and data on pollen grains and fern spores to form a picture of the living landscape before and after the K-T mass extinction.
Classroom Resource
This hands-on activity requires students to “visit” different K-T boundary sites.
Classroom Resource
A lesson in which students calculate the mass, size, and kinetic energy of the K-T asteroid based on the total abundance of iridium in the K-T boundary layer.
Classroom Resource
A hands-on activity in which students see first-hand the difference in foraminifera fossils below and above the K-T boundary.
Classroom Resource
A short article by Dr. Sean B. Carroll detailing the discoveries covered in the film The Day The Mesozoic Died.
Classroom Resource
A lesson in which students read a passage and answer questions about the information presented, testing their non-fiction reading comprehension.
Classroom Resource
A worksheet in which students calculate how much iridium was released, and eventually deposited all over the Earth, by the impact of the asteroid that caused the K-T extinction.
Classroom Resource
A worksheet in which students write down the evidence that led to the discovery that an asteroid struck Earth about 66 million years ago, causing a mass extinction. 

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