PENNSVALLEY
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Lesson 3: (Cont.)
Earth’s Time Zones and
the International Date Line
Part A –Time Zones (Cont.)
Let’s get back to time zones. Here is how you calculate time zone changes when traveling
west. ( ) Use a clock to help you.
•When travelers enter a new time zone headed west, they move their clocks back one hour, or
subtract an hour, for each different time zone.
• For example, betweenWashington, D.C., and Los Angeles, there are three different time zone
changes.
• Los Angeles is three different time zones to thewest ofWashington.
• The rule is to subtract one hour for each time zone. So you would subtract three hours from
whatever time it is inWashington.
• If it is 9:00 am inWashington, D.C., youwould take away three hours from 9:00 am.
• It would be 6:00 am in Los Angeles.
Here is how you calculate time zone changes when traveling east. (
) Use a clock to help you.
•When travelers enter a new time zone headed east, they set their clocks ahead one hour, or add
an hour, for each new time zone.
• For example, betweenWashington, D.C., and London, England, there are five different time zone
changes.
• London is five different time zones to the east ofWashington.
• The rule is to add one hour for each time zone. So youwould add five hours fromwhatever time
it is inWashington.
• If it is 9:00 am inWashington, D.C., youwould add five hours to 9:00 am.
• It would be 2:00 pm in London.
Entering a new time zone headedwest,
turn your clock back one hour.
Entering a new time zone headed east,
turn your clock aheadone hour.
Geography Skills
