In Classroom Instruction That Works (that is, real strategies for real learning) Robert Marzano's research shows that identifying similarities and differences is one of the most powerful thinking strategies we can teach. Helping students compare, classify, create metaphors and similies, and use analogies can boost student achievement up to 45 percentile points.
Tired of the ubiquitous Venn Diagram? Try these tech sites for a few fresh ideas:
1. Out on a Lim by Janice Lim, Michigan edtech expert
2. Analogix, an interactive site for older students
3. Similes and Metaphors on BrainPop (intermediate grades)