Rock Types Lab
In this lab, students identify rocks as metamorphic, igneous-plutonic, igneous-volcanic, sedimentary-detrital, or sedimentary-chemical on the basis of characteristics that are linked to their manner of formation. Groups of students classify sets of three rocks at a time, and get feedback from the TA, then switch sets. The focus is on helping them connect the "story" of different rock types (i.e., their history, which students should have previously learned about in some presentation of the "Rock Cycle") with different features that show up in the rocks.
Students should learn to connect the types of features they see in rock samples with the different ways in which rocks form. This provides a more connected framework of ideas to draw from when they start making more specific rock identifications.
Context for Use
This can be used in any introductory course where rock classification is taught.
Description and Teaching Materials
Student reading and forms (Microsoft Word 168kB Aug12 09)
to fill out during the activity.
Teaching Notes and Tips
I have noticed that students often learn rock classification backward–i.e., they learn to put names to rocks, then just memorize which names correspond to metamorphic, etc. Therefore, this lab was designed to given BEFORE other labs about identifying specific metamorphic, sedimentary, or igneous rocks.
The TA looks over the answers the students give, offers corrections, and watches for improvement with each set of new rocks. By "improvement" I mean an increased ability to identify the rock types of the samples and justify the identification based on the criteria given. The most important thing is for the students to be able to start to recognize in real samples the features discussed in the text of the exercise.
References and Resources