Density of Earth Materials
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: May 31, 2013
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Description and Teaching Materials
This activity modifies a typical density laboratory exercise to fit within a lecture session. Students are asked to compare the densities of six different rocks/minerals collected from six different environments. Based on the brief description of each rock the students are asked to first predict which rock has the highest density and which rock has the lowest density. The students are then asked to construct a hypothesis and test their hypothesis by calculating the density of the rocks. Students are then asked to apply information from lecture to place each rock in the appropriate layer of the Earth.
Student Handout for Density Assignment (Microsoft Word 120kB May31 13)
Teaching Notes and Tips
The version that I have posted here uses very generic rock descriptions, however if you know where your rock samples were collected, you could use more specific descriptions. For example, I have used granite collected from the Sierra Nevadas and basalt collected from the Juan de Fuca Spreading Center.
I typically use an andesite for the mystery rock. Of course, any granite or rhyolite would work as well. I don't use an ocean crust sample because all basalts look very similar and the students would probably be able to guess where it came from just by looking at it.
I observe the group discussions during class and try to address any misconceptions immediately. I also collect and grade the lab handout.