Lesson

# Clip 3/6: Lesson - Part 3

## Overview

Students conduct three rate experiments: stringing beads on a shoelace, picking up cubes with chopsticks, and counting rice. Each group conducts the experiment for a different amount of time: 10 seconds, 15 seconds, 20 seconds, and 30 seconds. Students are asked to write their results as a sentence and then to write results as a rate.

After the experiments the teacher debriefs the results as a whole class. "Who won?" "Why can't we tell from the raw data?"

## Teacher Commentary

COACH LINDA FISHER: The experiments allow students to have a hands-on experience with measuring rates. We want them to see that two units are involved. By giving groups different times, they can't directly compare data to find a winner. Hopefully the questions push them to see that either the number of objects or the time needs to be the same to compare the rates. When the teacher called on students, he purposely called on students from different groups, assuring that the time would be different, forcing the desired mathematics of finding equivalent ratios.