## Lesson: Finding Time IntervalsDeveloping the Concept

When children have a basic understanding of ordering events and elapsed time, they will be ready to explore other intervals of time—days, weeks, and months.

Materials: 12 blank calendar grids (Learning Tool 35 in the Learning Tools Folder), crayons or markers, a current calendar that can be taken apart

Preparation: Divide the class into 12 pairs or groups.

Prerequisite Skills and Concepts: Children should be able to identify days of the week and be familiar with the months of the year.

• Say: Just as a clock shows time in hours and minutes, a calendar shows time in days, weeks, and months.
Display a calendar for the current year and show the month of January. Say and read the name of the month together. Then have children note the days of the week.
• Ask: How many days are there in a week? (7) What day of the week is January 9? (Thursday) What is the date of the first Friday in January? (3)
• Ask: On what day of the week does this month begin? On what day does it end?
Discuss children's responses. Then assign the month of January to one of the groups. Give the group the calendar page to hold.
• Ask: What month comes after January?
If children have difficulty answering, show them the month of February on your calendar. Ask similar questions about each month as above. Assign the month of February to another group. Continue until each group has been assigned a month. Give a blank calendar grid and crayons or markers to each group. Have them make their own calendar page for their assigned month. Make sure that children have enough time to finish their pages.
• Say: I am going to name the month and date of a holiday. If that holiday happens during your month, find the date and draw a picture on your calendar.
Name holidays during the year.
• Ask: How can we put the pages of months you made in the correct order to make a classroom calendar?
Discuss children's responses. Then put the months in order and mount the calendar in your classroom. You may also wish to add birthdays and other special school days during the year.

Wrap-Up and Assessment Hints
To informally assess children's understanding of time, use your classroom clock and ask children to name the time to the hour or half-hour during the day. Use your classroom calendar to ask questions such as: Which month comes after March? How many Mondays are in December?