Lucky Luggage Tags: Elapsed Time to the Hour
Lesson 3 of 11
Objective: SWBAT calculate elapsed time to the closest half hour & hour using a number line.
Introduce/review key vocabulary term: elapsed. Discuss the homework from last night by inserting the word elapsed into the conversation. ("I see that you ate dinner at 5 p.m. and at 6 p.m. you were reading. An hour elapsed between the time you were eating dinner and the time that you were reading.") Depending on the background experience of your students, they can discuss w/partners what they know about time zone changes and/or you can explain using a globe/map/online tools. "Today we'll round airport arrival & departure times to the nearest hour & calculate travel time. (Enrich: add/subtract hours from the departure time to account for time zone changes) If needed, model sentences which use the words arrive and depart in a familiar context, & have them create oral sentences for the words. Then talk about how verbs can be nouns when they represent the concept of the action, not the action itself. (Arrival is the idea of coming to a place, and so on). I also quickly review rounding to closest hour .
This review of time to the hour is set w/in the context of a real-world task to provide students with diverse entry points. Student ability tends to range from not being able to tell time, to mastery of 2nd grade standards, to already being able to tell time to the minute. All students benefit from repeatedly counting across the twelve. This is consistently difficult for young learners because time is an abstraction and it is not in the base ten system.
I demonstrate how to set up a simple time number line w/demarcations for quarter hours or 5 min. intervals. Then I students choose from these sample elapsed time problem sets, for which they do not see the labels. I confer with them as they work. ReteachIf it’s 2 p.m. now, what time will it be in 5 hours? If it’s 5 p.m. now, what time will it be in 6 hours? If it’s 9 a.m., what time was it 3 hours ago? Crossing the 12: If it’s 9 a.m., in 8 hours it will be...? If it’s 1 p.m., 6 hours ago it was...? If it’s 8 p.m., in 5 hours it will be...? Time to 5 minutes , crossing the 12: If it’s 12:05 p.m. now, in 4 hours it will be...? If it’s 12:05 p.m. now, 4 hours ago it was...? If it is 9:35 p.m. now, in 3 hours it will be… ?
The idea of time zones is developmentally difficult for young students. Daily life provides them with no physical experience of being on a rotating & revolving planet. It is abstract to think about it being a different time in another part of the U.S. This video explains rotation & revolution with excellent supporting visuals. Start at 3:20, where days/time zones are emphasized. This resource supports a developing understanding of how one part of the Earth experiences sunrise at the same time that another region experiences sunset!
This elapsed time activity provides diverse entry points. Basic: SW practice adding on/subtracting hours from a given time. On level: SW develop understanding of time to the minute by rounding arrival & departure times to the closest hour. Enrich: SW calculate a trip's elapsed time. The PowerPoint, with a step-by-step process & visualizations, supports students in grappling w/the complexity of working w/time in multi-step, real-world scenarios. Show this real-time view of the Earth in a 2nd window to demonstrate different parts of Earth simultaneously experiencing different times of day.
This simple independent practice with finding elapsed time for direct flights will demonstrate how well students understood, and were able to apply, the concept of elapsed time as it was presented in today's lesson. Students drew open number lines and used the departure and arrival times (with one of them adjusted for time zone changes) as the start and end points.
Students record a learning/wondering on the Lucky Luggage exit ticket. These responses inform the next day’s instruction. Students also rank their feelings with smiley faces. This supports all young children, & especially those who are less confident, confused, or may not be able to express themselves in writing, as it requires both writing ability & metacognition.
Finally, I want students to enjoy math as these experiences set the tone for future academics. Students and I make colorful luggage tags w/ real airport codes. As we “travel,” I pass them out to students to acknowledge risk-taking, perseverance & a positive attitude.