The Rock Cycle: building descriptive skills

This activity is used in a lower division general education Earth Science course for non-majors (Geology of Local Parks). This class has short discussion sessions, a lab session, and several field trips.

Students do not need to have any background about the rock cycle or different rocks and minerals.

I use this at the beginning of a 4-week module on the rock cycle, and follow it up with a sequence of exercises about the different rock types, the minerals in those rocks, the common and rare minerals, what we use them for, and how we mine for them.

- There are different rock types
- Different rocks have specific and identifiable characteristics
- Importance of making detailed observations
- Utility of clear and detailed descriptions of observations

- Reflection about relating background ideas and information to observations
- Summarizing observations to make predictions

- Teamwork
- Sketching

Select a field area with different rock types (In this class we go to local parks in Los Angeles, where there are igneous, metamorphic, and sedimentary rocks exposed along short, wide, graded trails). Each outcrop has a different activity. At the first location we have an open group discussion and describe the outcrop as a whole discussing size, color, texture, surfical patterns etc. Then they get up close or break a portion off the outcrop and again as a group discussion describe the texture, homogeneity, crystal sizes, shapes, luster, etc. At another outcrop, students are partnered up and half the students take a piece of rock silently make observations and take notes in their notebook and the other half of the students do not get to see the rocks. Students with the rock describe what they see to their partner and have the partner draw it. Once they are finished the partner gets to see they rock they were drawing and the pair discusses what was confusing about the description that made it difficult to sketch. Then the partners switch. After each partner has had a chance to describe and sketch the entire class comes together for a group discussion about what common description components were is missing or needed for making better descriptions so that their partner can create a better representation of the rock. Next have each person individually spend time looking at the entire outcrop and answer the following prompts in their notebook: "I notice...", "I wonder..." and "It reminds me of...". Move to a new outcrop and play a version of hot potato. groups of 4-5 students select one rock from the outcrop. The first person takes a quick look and shares one observation, then passes it to the next, who also shares one observation, they continue around in a circle trying to make a group list of as many observations as they can. Make your way to several other outcrops switching between these different activities that involve individual, small group, and large group discussions from observations and sketching. You should see a shift from more time spent figuring out what is missing in the descriptions to more time spent synthesizing all the different observations. If you are in a location that allows for rocks to be taken from the area, take 1-2 samples from each outcrop for future classroom work and comparison with in-class hand-samples.
Example of activity guide (some parts specific to Griffith Park) (Microsoft Word 2007 (.docx) 25kB Feb5 24) 
Geologic map of Griffith Park (Acrobat (PDF) 221MB Feb5 24) 

This does not have to be done in the field, it can be in a classroom or online setting with hand samples or images, however, the field setting helps students see hand samples in a physical/real context and often hand samples are better/curated than samples in the field so it helps to see that difference.
Students are very resistant to sketching, I try to emphasize that they are trying to help their partner become better at making observations and describing those observations, so the goal is not making a good sketch, but instead showing their partner where improvements can be made in describing their observations. That being said, this particular class did cover strategies for making sketches and basic nature journaling practices before this activity.
Be sure to talk about the field area before going on the trip, give them as much info as possible about bathroom access, shade, clothing to wear, water, physical conditions, etc. We want them to focus on the observations and not the potentially novel space they may never have been in before.

- Formative assessment: in the field through individual check-ins as students are working, and through the group discussions
- Formative assessment: upon returning/leaving the field glance through their notes in their notebooks and provide feedback but no grades
- Graded assessment (formative): final reflection questions about what they learned, what was new/different, what was challenging, what new questions they have, etc.
- Graded assessment (summative): After several more weeks discussing the three different rock types and looking at hand samples of various rocks and minerals, students return to the samples we collected on our trip, make a detailed descriptions, and name the rock types.