Calculating Iridium Fallout From an Asteroid Impact

Description
This activity allows students to calculate how much iridium was released, and eventually deposited all over the Earth, by the impact of an asteroid that struck Earth 66 million years ago. It supports concepts presented in the short film The Day the Mesozoic Died.
This activity challenges students to develop a reasoned estimate of the amount of iridium contained in an asteroid similar in size and composition to the one that struck Earth 66 million years ago, causing the K-Pg (formerly referred to as K-T) mass extinction. Several correction factors and assumptions are introduced to carry out these calculations.
Student Learning Targets
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Apply the law of conservation of mass to estimate the abundance and distribution of a substance, such as iridium.
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Evaluate a hypothesis by forming rough estimates to verify data presented in support of the hypothesis.
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Synthesize information from multiple sources to develop a coherent understanding of an event.
Estimated Time
Key Terms
chondrite, Cretaceous Period, iridium, meteor, Paleogene Period, “parts per” notation, stratosphere, Tertiary Period
Primary Literature
Alvarez, Luis Walter Alvarez, Frank Asaro, and Helen V. Michel “Extraterrestrial cause for the Cretaceous-Tertiary extinction.” Science 208, 4448 (2008): 1095–1108. https://doi.org/10.1126/science.208.4448.1095. To access this article, set up a free AAAS account.
Smit, J., and J. Hertogen. “An extraterrestrial event at the Cretaceous-Tertiary boundary.” Nature 285, 5762 (1980): 198–200. https://doi.org/10.1038/285198a0.
Terms of Use
Please see the Terms of Use for information on how this resource can be used.
Version History
NGSS (2013)
HS-ESS1-6; SEP1, SEP5
Common Core (2010)
Math.N-Q.1, Math.A-SSE.1, Math.A-CED.1, Math.A-CED.4, Math.A-REI.3; MP1, MP2
Vision and Change (2009)
CC5; DP1, DP2