Many children enjoy collecting items such as seashells, state quarters, and trading cards. Asking students to think about the ways in which similar items differ, how objects can be grouped by a common characteristic, and how groups can be subsets of a larger category leads to an understanding of fundamental mathematics and science concepts: sets, relationships, and representation of data. In the following lesson, students observe similarities and differences among leaves, consider ways in which leaves can be sorted, and group leaves of common properties into circular areas (Venn diagram).