Is It a Mineral?

The Activity

I give six or seven objects to four small groups of three to five students. All groups have the same six or seven objects. All are asked to work with their group to determine which are minerals and which are not and to determine why. After a few minutes I call on individuals in the class to choose an object and tell me whether or not it is a mineral and why. I try to draw out one of the characteristics of minerals from each individual. If an individual is stuck, I ask other students to chime in with help. I write the characteristics on the board as students mention them and I give brief explanations as needed. After calling on one individual from each group the class typically has come up with all of the characteristics of minerals and, usually, defined the difference between minerals and rocks. Objects that I typically use are quartz, obsidian or glass, granitic rock, wood block, copper block, plastic, aluminum, and ice in water. This exercise sets the stage for an active class consisting of discussions and small group activities throughout the semester.