Most of us learned rock and mineral identification and classification by comparing samples in a box to a chart listing observable features. Those who have used this approach in the classroom know that this activity promotes a student perception that the ultimate goal is to make a close match with the chart and discover what name this sample has been given by the scientific community. A new activity has been developed that keeps the student’s focus on recognizing similarities and differences between specimens and constructing an understanding of defining characteristics.

The activity was developed by the author to teach minerals and rocks. However, this activity is adaptable to the study of anything that can be categorized and classified. If there is a need for the student to construct an understanding of defining characteristics and diversity within a larger set, this activity can be used.

In this activity, the students are broken into groups. Each group is given a different set of samples. They are not given any charts or other prefabricated means of organizing them. The students are asked to create a classification scheme for their samples. The goal is to create a system that anyone could use to correctly identify each specimen. The students are given minimal guidance. The students are asked to trade their samples and charts with another group. The groups are then asked to try out each other’s schemes. Finally, the class is asked to reflect on their practices.

This activity is student-centered, constructivist, and focuses primarily on what is most important for our students. They develop a familiarity with the features of their sample set. They construct a classification system, thus increasing their understanding of distinguishing features and organization within their sample set. Finally, they discover the processes by which the scientific community recognizes and categorizes materials. These things facilitate a real understanding of rocks and minerals and lead to synthesis and later application.