Cutting Edge > Courses > Petrology > Teaching Activities > Crystal and Glass Formation from a Melt and a Glimpse into Archaeometallurgy Through the Eyes of a Binary Eutectic Phase Diagram

Crystal and Glass Formation from a Melt and a Glimpse into Archaeometallurgy Through the Eyes of a Binary Eutectic Phase Diagram

Dori Farthing
,
University of Dayton
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This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.


This page first made public: Jul 17, 2008

Summary

This lab gives students the opportunity to investigate crystallization processes and textures. Students experiment with a crystalline wax, studying how/where the crystals form, how to get crystal-free material, and how different cooling rates affect crystal size and distribution.

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Context

Audience

This exercise is designed for a sophomore or junior level required course in petrology.

Skills and concepts that students must have mastered

Students should have a basic understanding of how to read a phase diagram.

How the activity is situated in the course

This is a 3-part stand-alone activity.

Goals

Content/concepts goals for this activity

I have discovered that students seem to struggle with the idea of quenching and how it serves a snapshot of a phase diagram at a set temperature and composition. This 3 part lab walks students through self-designed experiments, glass in real samples, and then to a binary eutectic phase diagram exercise.

Part three of the lab brings to light the idea that petrologic concepts extend out of the world of geology. Part 3 is an exercise where students address archaeometallurgical questions based upon information from a phase diagram.

Higher order thinking skills goals for this activity

This activity involves data analysis.

Other skills goals for this activity

Description of the activity/assignment

This lab gives students the opportunity to investigate crystallization processes and textures. Students experiment with a crystalline wax, studying how/where the crystals form, how to get crystal-free material, and how different cooling rates affect crystal size and distribution. Students can even create their own pillow lavas and flow/cooling textures. The experiments also provide an opportunity to clarify the idea of quenching for students. Once students understand quenching, they have an easier time completing the included exercise which involves looking a binary eutectic phase diagram and the modal abundances of glass and crystals in a real sample. The phase diagram and modal information are used to determine a melting/quenching history and composition for a historical sample of metallurgical slag.

Determining whether students have met the goals

Students have met the goals of this assignment if they answer the assigned questions thoroughly and accurately.

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