World Clocks (Or, "Is it Time for Lunch Yet?") By Journey North Teacher Cathy Plaehn Background During Mystery Class, students receive sunrise and sunset times from places around the world. The "World Clocks" activity is a constant reminder that sunrise and sunset occur because the Earth is spinning on its axis. The cycle of day and night is a familiar experience. However, the Earth's 24-hour cycle can be hard to visualize. Clocks and time zones make a fun and familiar entry point. Students can imagine what people around the globe are doing at certain moments in time. They can see how our lives are affected by the Earth's daily rhythms. This repeated experience helps students build an understanding of the Solar System. Materials The classroom clock Two or more inexpensive travel or alarm clocks Optional: Display a world time zone chart below the clocks. (There are several links on Wikipedia.) Exploration Set one of the clocks on Greenwich Mean Time and label it Greenwich, England. Choose a variety of locations for the other(s), such as Perth, Australia; Istanbul, Turkey; Bombay, India. Try to spread them out enough so that you can see large differences in time. (If there is some class connection to a location in the world, use that location.) Label each clock with the location and the deviation from your local time. This will help students understand when it is a different day in two locations. Wait until someone asks what the clocks are for and then begin a discussion about possibilities. Once the clocks become a focus in the classroom, refer to them routinely when an opening arises. For instance, someone in the class may ask "Is it lunch yet?" The class has already been interrupted so seize the opportunity. "Are they eating lunch in any of the cities on the clocks?" Or someone may say, "I'm tired, can we take a nap?" You can reply, "No, but where in the world would you be sleeping at this time?" If you have a few minutes until the end of class you can ask, "If I wanted to talk to someone in England, would they be happy or upset to get my call right now?" Use the words "local time" and "Universal Time" frequently. "What time is it in Turkey, local time?" "What time is it in Universal Time or Greenwich Mean Time?" Periodically challenge students to model the positions of the Sun and Earth at various times of the day, using a globe and flashlight. Ask them, "How are the Sun and Earth positioned right now?" Then, "How will this change during the next few hours?" Have them turn the globe in the proper direction (counter clock-wise) to show how the Earth spins on its axis. This lesson is excellent preparation for a Mystery Class challenge students receive each year on the Spring Equinox. Journaling Questions Why are clocks set to different times at different places on Earth? Explain the concepts of "local time" and "Universal Time." What natural events is local time connected to? When is the concept of "Universal Time" important? 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. This Season Teachers Kids Orientation Registration Search Copyright 1997-2009 Journey North. All Rights Reserved. Questions or comments? Contact us.