Keep the materials in a bag so the students cannot see them. Organize the students into groups of three. Tell them that you are going to show them four objects and that they will have three minutes to discuss what those objects have in common and to record their responses on paper.Withdraw the objects from the bag one at a time, in the following order: the vinyl record, the cassette tape, the compact disc, and the organism. Re- peat the question, "What do these objects have in common?