E2.3 Solve problems involving elapsed time by applying the relationships between different units of time.
Activity 1: What Time Will I Return from the Field Trip?
Material
A watch with a dial or a clock with hands (the clocks used in the primary grades are ideal because you can move the hands) and an open number line.
Instructions
Set the watch or clock to 9:15 a.m.
Pose the following questions to the students and ask them to explain their reasoning:
- How long would it take to get to an event if you leave now and arrive at 10:00 am?
- How long is the event if it ends at 1:30?
- If you left right after the event, what time will you be back at school?
Ask the student how long it would take to get to a location if you had to leave now and were expected at 10:00 am.
Ask them to explain their reasoning.
Ask the student how long the activity will last if it ends at 1:30.
Ask them to explain their reasoning.
Ask the student what time we will be back at school.
Ask them to explain their reasoning.
Continue the questioning with other durations (for example, the time remaining from the return to the end of the school day).
Source: adapted and translated from L’@telier - Ressources pédagogiques en ligne (atelier.on.ca).
Activity 2: A 24-Hour Day?
Instructions
Discuss with students the different activities they do on a weekday (for example, sleeping, eating, going to school, playing at recess, participating in extracurricular activities, playing outside). Ask them to estimate how long each activity takes.
When all students have finished, lead a brief discussion about the results. Ask questions such as:
- How many hours do you estimate to be active in a day?
- How many hours do you estimate your day to be?
- How might you explain the difference between these two answers?
- Which activity lasts the longest? How do you know? Which activity lasts the shortest? How do you know?
- Which of your activities last less than an hour?
- If you were asked to estimate the amount of time you spend on these same activities on a weekend day, would the results be the same or different?
Then ask students to determine the actual time for each of the activities over the next 24 hours using an open number line. Ask them to compare the actual time to complete each of the activities to the estimated time. Lead a discussion and ask questions such as:
- How did you determine the actual time spent on each activitý?
- Have you had any problems? Which ones?
- How do you explain the differences and similarities between your estimated and actual durations?
Source: translated from Guide d'enseignement efficace des mathématiques de la 4e à la 6e année, Mesure, p. 151.
Activity 3: Months and Days (Calendar)
Instructions
Discuss with students various upcoming events in the year (for example, vacation break, the next holiday or instructional day, March break, or the end of the school year).
Ask students questions such as:
- What is the date (of the event)?
- How long will this event take place and how do you know?
Note: Encourage students to use effective models, such as an open number line, to determine duration. Clarify that different units of time may need to be used to determine duration accurately (for example, the next vacation will be in two months and 11 days).