Is it a Meteorite?

In-Class Activity 1_Meteorites and Impact Craters

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Figure 1 Meteor Crater, AZ

Provenance: Image Credit: Photograph by David Roddy, United States Geological Survey.
Reuse: This item is offered under a Creative Commons Attribution-NonCommercial-ShareAlike license http://creativecommons.org/licenses/by-nc-sa/3.0/ You may reuse this item for non-commercial purposes as long as you provide attribution and offer any derivative works under a similar license.

Julia Kahmann-Robinson PhD and Marjorie Chan PhD, University of Utah Department of Geology & Geophysics

Purpose

Discover the criteria by which meteorites are identified.

Preparation

Gather hand samples of rocks and meteorites (at least 4 in total for the exercise) or use the Image File provided in the learning module Meteorites and Impact Craters

Engage

Observe the rocks provided by your instructor. Mark Yes or No for whether or not you think the rock is a meteorite. Also note if the rock is: igneous, metamorphic, or sedimentary. Upon which criterion are students identifying whether or not a rock is a meteorite?

What criterion/criteria are you using to identify whether or not a rock is a meteorite? Please explain below:

Explore

Criteria to identify a meteorite in hand sample (NASA DAWN Mission: http://dawn.jpl.nasa.gov/meteorite/experiment.asp ). Does the specimen [have]?

1. Presence of a fusion crust?
2. Presence of shiny metals?
3. Presence of regmaglyps (thumbprints)?
4. Attracted to a magnet?
5. Density greater than a typical Earth rock?
6. Presence of chondrules?

Go through these criteria as the discussion with the students would indicate in Engage. Ultimately, however, chemical analyses will be crucial to positive identification.

Explain

Read about meteorite vs. meteor-wrongs. Have students vote on what website they think gives the best presentation (and/or give some alternate sites). Possible websites to use are below.

http://meteorite-identification.com/

http://www.littlewolf.us/meteoriteormeteorwrong.html

http://www.meteorites-for-sale.com/meteorite-identification/meteor-right-wrong.html

Elaborate

Discuss how many meteorites are from Mars. Is the number single digits, tens, hundreds, or thousands? Have students guess and then they can check their guess at this website. http://www2.jpl.nasa.gov/snc/

What criteria do we use to tell if a meteorite is from Mars?

http://www.imca.cc/mars/martian-meteorites.htm

Evaluate

What happens when a meteorite hits a planetary surface? How big will the crater be?

Observe the crater in Figure 1. This crater, known as Meteor Crater in Arizona, measures 0.737 miles (1.19 km) in diameter and 570 feet (170 m) deep.

1. How big do you think the meteorite was?
2. What factors influence the size of the crater. List at least 5 below:

Calculate your own crater size!

1. Using the below link, calculate the size of 3 craters that will form when you change varying parameters. Record the parameters and results below. Consider #2 as you change your parameters.
2. What parameter do you find to be the most influential in the size of a crater

Google Mars & Craters

1. Using Google Earth find the region Mawrth Valles (22.43_N 343.03_E) in the Mars navigation. Using the ruler tool try and determine the average diameter of craters in the region. Write the average below.
2. Are most craters relatively large or small? What might this say about the ages of these craters?

Test your skills:

Which image below is a meteorite, Figure 2 or Figure 3? List your criteria.

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Figure 2

Provenance: Image Credit: NASA
Reuse: This item is offered under a Creative Commons Attribution-NonCommercial-ShareAlike license http://creativecommons.org/licenses/by-nc-sa/3.0/ You may reuse this item for non-commercial purposes as long as you provide attribution and offer any derivative works under a similar license.

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Figure 3

Provenance: Image Credit: Levi Huish (2012)
Reuse: This item is offered under a Creative Commons Attribution-NonCommercial-ShareAlike license http://creativecommons.org/licenses/by-nc-sa/3.0/ You may reuse this item for non-commercial purposes as long as you provide attribution and offer any derivative works under a similar license.