Duration and Elapsed Time
Warm-up
The tide was high at 6:35 am. The next high tide is 12 hours 25 minutes later. When is the next high tide? 6:35 + 12:25. Hours: 6+12=18:35. Minutes: 35+25=60 = 1 extra hour. 18:35 + 1:00 = 19:35 = 7:35 pm. This is elapsed time in a real ecological context.
Explore
Natural cycle elapsed time challenge: each group investigates one natural cycle (tidal, lunar, seasonal, migration). They research the cycle length and solve 3 elapsed time problems using that cycle. Share: if low tide was at 3:18 pm, when is the next low tide? What day is the next full moon after today?
Consolidate
Practice
Students calculate elapsed time for 6 problems (including 2 crossing noon), solve 2 natural cycle problems, and map a school-day schedule on a timeline. Exit ticket: a movie starts at 7:25 pm and lasts 2 hours 15 minutes. When does it end?
Exit ticket
Students calculate elapsed time for 6 problems (including 2 crossing noon), solve 2 natural cycle problems, and map a school-day schedule on a timeline. Exit ticket: a movie starts at 7:25 pm and lasts 2 hours 15 minutes. When does it end?
Count up: 9:47 to 10:00 = 13 min. 10:00 to 1:00 pm = 3 hours. 1:00 to 1:15 = 15 min. Total: 3 hours 28 minutes.
11:20 + 4 h = 3:20 pm. 3:20 + 35 min = 3:55 pm. The journey ends at 3:55 pm.