Peritectic Phase Diagram

Dexter Perkins
U N Dakota
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This activity was selected for the On the Cutting Edge Exemplary Teaching Collection

Resources in this top level collection a) must have scored Exemplary or Very Good in all five review categories, and must also rate as “Exemplary” in at least three of the five categories. The five categories included in the peer review process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
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This page first made public: Oct 3, 2011


An exercise to help students figure out what is going on with peritectic phase diagrams. It is NOT trivial.

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I use this in our undergraduate petrology course.

Skills and concepts that students must have mastered

They must have completely mineralogy and know the basics of mineral formulae. It is helpful if they have already been introduced to peritectic diagrams and incongruent melting, as well as to the lever rule, in some way.

How the activity is situated in the course

This is done in-class by groups of students. It can be a challenge -- if they can do this it means they fully understand such diagrams. If they cannot do this, then they need to keep practicing.


Content/concepts goals for this activity

No content goals, really. This is just to check to see if they understand the diagrams.

Higher order thinking skills goals for this activity

This is not low level recall or even simple application/interpretation. Logic and reasoning must be applied.

Other skills goals for this activity

Description of the activity/assignment

This is a 1-page worksheet exercise involving a peritectic phase diagram. To complete it, students must REALLY know how to use such diagrams.

Determining whether students have met the goals

There are correct answers to all questions, so this can be graded easily. Less easy is to figure out what went wrong, and what to do about it, if students do not get the correct answers.

More information about assessment tools and techniques.

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