World Clocks
Exploring Local Time and Time Zones

 Los Angeles Greenwich Baghdad Local Time Universal Time

Background
During Mystery Class, students receive sunrise and sunset times from mystery locations around the world. Each location provides local time, according to their own time zone. In this activity, clocks are displayed that are set according to local time in various time zones. Students imagine what people around the globe are doing at certain moments in time. The clocks are a constant reminder that the rotating Earth causes the daily cycle and affects sunrise and sunset times.

 Essential Question Why are clocks set to different times at different places around the world?

Teaching Suggestions

•  Photo: Sharon Angal Clocks in the Classroom Quatama Elementary
Set up a row of clocks. Set one of the clocks to Universal Time and label it Greenwich, England. Choose a variety of locations, such as Los Angeles and Baghdad.
• Arrange the clocks geographically according to longitude. Greenwich is 0 longitude. Put clocks east of Greenwich to the right, and clocks west of Greenwich to the left.
• Display a globe or world time zone chart beside the clocks and plot each location.
• Include longitude data for each location as part of the display.
• Refer to the clocks at various times during the day. For example, at lunch time explore what people around the world might be doing at the same moment.
• Use the sunrise animation to remind students that the rotating Earth causes sunrise and sunset to occurr at different times around the world. Divide the class into groups, one for each clock. Challenge students to raise their hands as sunrise occurs at each location.

Discussion Questions

• What is the difference between "local time" and "Universal Time"?
• How are time zones used?
• When is the concept of "Universal Time" important?
• How is Greenwich, England related to time?
• How are time and longitude related?
• What causes day and night to be different in different parts of the world?
• How would your day be different without clocks?
• What if the world had no time zones?

National Math Standards: Measurement
Understand measurable attributes of objects and the units, systems, and processes of measurement.

National Geography Standards: The World in Spatial Terms
How to analyze the spatial organization of people, places, and environments on Earth's surface.