A96, Building large models to show equivalence, a generalization (side view), Grade 4, October 11, 1993, raw footage

During this session, conducted as a whole class discussion, Researcher Maher revisited the problem that the students had worked on during the previous three sessions: Which is larger, two thirds or three fourths, and by how much? First, she asked students to show her the smallest model that could be built to show the difference between the two fractions. After it was built, she asked the students to convince her that it was indeed the smallest model possible for this task. Then, she asked the students to find the model that would be the next in size, and the students produced a model that was twenty-four cm in length, showing the difference to be two twenty-fourths. Following this, Erik, David, and Meredith produced their flawed forty-eight cm model, and the students discussed why it did not work. Then, Andrew and Jessica reproduced the forty-eight inch model that they had found using large-size Cuisenaire rods at the front of the classroom. Students then noticed that the models were doubling in size from the previous one built, and began to conjecture how large each successive model would be. Researcher Maher concluded the discussion by asking the students to think about the question: Is there a biggest model?Robert B. Davis Institute for Learning. (1993). A96, Building large models to show equivalence, a generalization (side view), Grade 4, October 11, 1993, raw footage [video]. Retrieved fromTranscript is also available