Greenwich Mean Time
and World Time Zones

When to Phone a Friend (and avoid an international incident)

"Grrrr! Why are you calling me in the middle of the night?!"

Baily lives in New York and one night after dinner she decided to give her friend Max a call. Max recently moved to Venice, Italy, and she wanted to see how he was doing in his new home. But Max's father answered the phone sounding pretty grumpy, and he sternly told Baily that it was after midnight there, and asked her why she would call in the middle of the night when everyone was sleeping!

How could Baily have avoided this international incident? What to do? GMT to the Rescue!

Try This! Help Baily plan her next call to Max.
Schedule a call at a time when both Baily and Max are still awake. Using the Time Zones map below, plan the call:

1) Using her local time, what time would Baily need to call Max so her call didn't wake up Max? (or his Dad!)

2) What local time would it be in Venice?

3) Once you've figured that out using local times, figure out what time Baily's call would take place using GMT.

4) Using your own local time, what time would you call Max?
Map of World Time Zones

Click Map to see all
24 time zones

National Math Standards

Use mathematical models to represent and understand quantitative relationships.

Specify locations and describe spatial relationships using coordinate geometry and other representational systems.

Understand measurable attributes of objects and the units, systems, and processes of measurement.

Apply appropriate techniques, tools, and formulas to determine measurements.

Problem Solving:
Build new mathematical knowledge through problem solving.

Use representations to model and interpret physical, social, and mathematical phenomena.

National Geography Standards

The World in Spatial Terms:
How to use maps and other geographic representations, tools, and technologies to acquire, process, and report information.

How to analyze the spatial organization of people, places, and environments onEarth's surface.

Human Systems:
How forces of cooperation and conflict among people influence the division and control of Earth's surface.