In this exploration lesson, students use stopwatches to measure time as a physical quantity. They might, for example, time how long it takes to write the fact 7 × 8 = 56 forty times or measure how long it takes to write numbers from 0 to 100. Students then time their own segments as they run a relay, which helps build understanding of the continuity of time by seeing their segment within the number of minutes it takes the whole team to run.