# Fictional Phase Diagram

Phase diagrams

##### Equipment:

Transparency of the fictional phase diagram attached and flash cards, each one having a microstructure in color that corresponds to a dot on the diagram. Each card is labeled with a letter, and each numbered dot has one lettered flashcard that has the corresponding microstructure on it. The answers are below.

##### Procedure:

There are many different ways in which this can be used. For one, the instructor can go through with the class in how to solve the problem of various microstructures and how to match them with the appropriate temperature/composition dot on the phase diagram. In recitation sections, additional notecards can easily be made so that students can work on this together in groups before the instructor goes over the answers. It is even possible that the diagram can be left on the overhead projector and the cards passed around to each student for them to try and figure it out themselves for a quiz.

##### Science:

This is a good way to teach students how to read a phase diagram. I remember the learning process concerning microstructures and their relation to phase diagrams to be confusing. By using this fictional diagram it may be easier for students to learn. A good concept portrayed in this learning procedure is the lever rule, and using it to determine the amounts of each phase at a specific location in a two phase region on a phase diagram. Remarks: Attached are pictures of what the microstructures look like. These could be used as a reference to make additional cards. Also the amounts of phases shown on the cards are not exact. What is important to do is to compare the various microstructures available and decide which one best represents each dot on the diagram. The main purpose of this exercise is to generally understand how to read a phase diagram. The determination of the precise amounts of phases in a two phase region is covered in detail in the Lever Rule presentation.

Answers: 1)d 2) l 3) h 4)j 5)a 6)k 7)e 8)g 9)f 10)i 11)b 12)c