Math Background

Lesson: Finding Time Intervals
Introducing the Concept

Materials: a long piece of string or yarn, clothespins, large index cards, markers, analog clock

Preparation: Hang string or yarn as a clothesline at the front of the classroom. Draw a chart on the chalkboard. On index cards, draw simple pictures or write phrases to represent daily classroom activities.

Prerequisite Skills and Concepts: Children should have an understanding of time to the hour and half-hour.

Ask children to help you list classroom activities for the day on the chalkboard. Discuss the times when these activities will happen. Have volunteers help you write the time to the nearest hour or half-hour next to each activity on the list. Then have volunteers help you hang the index cards in order on the clothesline.

  • Ask: How can I show the time on my clock when our (morning circle) begins?
    Children should name the numbers to which the hour and minute hands point, show the time on the clock, and write the time as it would appear on a digital clock.
    Clock showing nine o'clock
  • Say: I want to find out how much time passes from when (reading) begins until (math) begins. Let's use a clock to help.
    Move the hour and minute hands to show the passage of time. Name each hour that passes.
  • Ask: What time is it now?
    Have children name the correct time.
  • Ask: How many hours have passed?
    Discuss the answer. If necessary, model the passage of time again with the analog clock.
  • Say: Let's choose two more activities that measure 1- and 2-hour intervals and use a clock model to find out how much time passes.
    Have volunteers point to activities on the clothesline. Repeat the activity with different times based on the activities on the clothesline.

Houghton Mifflin Math Grade 1