Geochemistry - Soils Analysis

Cynthia Fadem
,
Earlham College
Author Profile
Initial Publication Date: June 29, 2010

Summary

Students conduct a geochemical analysis of a soil. Choice of activity and group-size allows students to play to their strengths. Each group chooses one of the following analyses: conductivity buffer solution, conductivity, acidity, mineralogy, grain size, or loss on ignition. The follow-up lab requires that they evaluate each group's data presentation and interpret the combined dataset.

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Context

Audience

GEOS 316 Geochemistry: mid-level course for majors

Skills and concepts that students must have mastered

lab safety, thermodynamics and kinetics, rock & mineral chemistry (Many students in this class had already taken Soils as well.)

How the activity is situated in the course

part 1 of 2

Goals

Content/concepts goals for this activity

basic reagent mixing, soil biophysical analysis, data representation (visual)

Higher order thinking skills goals for this activity

data representation (Follow-up lab included critical analysis, comparison, and combination of the datasets collected here.)

Other skills goals for this activity

working in & among groups (i.e., organization of space among multiple groups with mutually exclusive goals)

Description of the activity/assignment

Students conduct a geochemical analysis of a soil. Each group chooses one of the following analyses: conductivity buffer solution, conductivity, acidity, mineralogy, grain size, or loss on ignition. As this lab falls somewhere between the middle and end of the course, students are versed in various chemical methods. This lab reinforces those skills while forcing students to organize their time and be patient with each other while conducting careful lab science. The samples used for this lab were from a Bronze-Age archaeological site in Kazakhstan, but any samples could be substituted. To encourage free-thinking concerning their representations (and interpretations in the follow-up lab), as little background information as possible was given.

Determining whether students have met the goals

For this lab, a student's engagement with the chosen activity (and the ensuing data) and willing cooperation with their classmates were the most important factors. All (9) of the students did well on this lab (possibly owing to the particular orientation of this group of students to lab activity), but a few lagged in the follow-up analysis lab.

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