# Elapsed Time Background Information for Teachers, Families and Caregivers

This page provides information to support educators and families in teaching K-3 students about elapsed time. It is designed to complement the Elapsed Time topic page on BrainPOP Jr.

Review with children that elapsed time is the amount of time that passes between one point in time to another. Explain that we can measure elapsed time by counting up or by using clocks, stopwatches, and digital stopwatch websites and apps. Have children use a stopwatch, digital stopwatch, or the second hand on a clock to measure how long it takes them to complete an activity, such as hopping across the room or putting away a book or toy. How long did the activity take? Remind children that they might measure elapsed time in seconds, minutes, hours, days, or even years!

Present the following scenario: A painting class begins at 7:40 and ends at 8:15. How long is the class? Solve the problem together using different strategies. Set an analog clock to 7:40 and move the minute hand as children count up by fives until the time is 8:15. Then present another scenario: Moby looks at a bus schedule. The time is 3:22 and the next bus is at 5:29. How much time does Moby have until the next bus? Use an analog clock set to 3:22 and have them count up 3 minutes until 3:25. Remind children that 3:25 is an easier number to work with. Then have them count up an hour to get to 4:25, and then another hour to 5:25. Since the bus leaves at 5:29, they have to count up 4 more minutes. Then have the students add the minutes and hours together. Moby has 2 hours and 7 minutes until the next bus. Challenge children to count up the hours and minutes in another way: They can start at 3:22 and count up 2 hours until 5:22. Then they can count up 3 minutes to get to 5:25, and count up another 4 minutes to get to 5:29. Encourage children to use landmark numbers to help counting up.

Model different strategies children can employ to calculate elapsed time. Some children may find using a chart clearer and easier. Using the previous problem, set up a T-chart and write the start and end times. Then count up hours and minutes together and fill in the chart. Model how to add up the minutes and hours to calculate elapsed time. Next, using the same problem, calculate elapsed time by using a number line. Write the start time and end times at the each end of a number line and then use landmark numbers as you count up hours and minutes. Remind children that they can use different strategies to find the one that works best for them.

Discuss the importance of elapsed time with children. How do we use elapsed time in our day-to-day lives? How might knowing how long certain activities take allow us to plan our day or budget our time? If we know how long a bus takes, how does that help us plan to arrive somewhere on time? If we know a movie begins at 7:00, and it takes 15 minutes to get to the theater, how can knowing elapsed time help us plan when we should leave? Help children understand how knowing how to calculate elapsed time helps us budget our time and arrive on time!