Some Simple Hands-On Activities for Teaching Key Concepts in Soil Science.

The immense complexity and foreignness of the below-ground world make introductory soil science a struggle for many students.  The objective of this study is to develop and evaluate hands-on activities designed to improve student comprehension of key concepts in soil science.  The activities introduced here each involve some tangible object to help students relate abstract concepts to their real-world experience.  These activities include: 

1. Specific surface area of wooden blocks:  The students are given large and small wooden blocks and asked to determine the specific surface area of each.  This activity helps the students understand the relationship between particle size and specific surface area.
2. Phosphorus fixation skit:  Several students are assigned the role of P-fixing minerals and one student is assigned the role of a plant growing in the soil.  Some small objects, like ping-pong balls, are used to represent phosphate ions.  The class must figure out how many phosphate ions need to be added to the soil in order to provide the plant with enough phosphate to grow in the presence of the P-fixing minerals.  This activity helps the students understand what P-fixation is and how it affects plant growth.
3. Liebig paper cups:  This activity takes a hands-on approach to the “leaking bucket” model for Liebig’s Law of the Minimum.  The students are provided with paper cups, which are divided into panels that are cut to different lengths, and labeled with different plant nutrients.  The students determine what would happen to the cup’s ability to hold water if different panels on the cup were lengthened.

Preliminary qualitative observations of the application of these activities suggest that the hands-on learning activities were effective.  In the coming year, quantitative data will be collected to test the effectiveness of these activities among students in courses designed for majors and non-majors.