Time zones

How the Earth's rotation creates 24 different time zones across the globe

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Try each question. If you're stuck, leave it and come back. The answer key is on the last page.

1
How many time zones are there around the world? A) 24 B) 12 C) 60 D) 100
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2
Fill in the blank. The time zone at the Prime Meridian is called ___ Mean Time.
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3
True or false? The Earth rotates 15 degrees every hour. A) True B) False
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4
True or false? The UK is in the GMT time zone (Greenwich Mean Time). A) True B) False
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5
If it is 12:00 noon in London (GMT), what time is it in New York (GMT-5)? A) 7:00 am B) 5:00 pm C) 12:00 noon D) 5:00 am
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6
If it is 9:00 am in London (GMT), what time is it in Tokyo (GMT+9)? A) 6:00 pm B) 12:00 noon C) midnight D) 3:00 am
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7
True or false? Places to the east of the Prime Meridian are ahead of GMT. A) True B) False
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8
Fill in the blank. The International Date Line is at ___ degrees longitude.
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9
If it is 8:00 pm on Monday in Sydney (GMT+10), what time and day is it in London (GMT)? A) 10:00 am Monday B) 10:00 pm Monday C) 6:00 am Tuesday D) 8:00 pm Sunday
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10
True or false? Every country uses exactly one time zone. A) True B) False
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Answer key

Time zones · for parents and teachers

1
24
There are 24 main time zones, one for each hour of the day. The Earth rotates fully once every 24 hours.
2
Greenwich
Greenwich Mean Time (GMT) is the baseline time at the Prime Meridian. UTC (Coordinated Universal Time) is the modern equivalent.
3
True
The Earth turns a full 360 degrees in 24 hours. 360 divided by 24 equals 15, so it turns 15 degrees per hour, which is why each time zone covers 15 degrees of longitude.
4
True
True. The UK's standard time zone is GMT, set by the Greenwich Meridian.
5
7:00 am
New York is GMT-5, which means it is 5 hours behind London. 12:00 noon minus 5 hours equals 7:00 am.
6
6:00 pm
Tokyo is GMT+9, which means it is 9 hours ahead of London. 9:00 am plus 9 hours equals 6:00 pm.
7
True
Eastern places are ahead of GMT because the Sun rises there first. Western places are behind GMT.
8
180
The International Date Line runs near 180 degrees longitude in the Pacific Ocean, opposite the Prime Meridian. Crossing it changes the calendar date by one day.
9
10:00 am Monday
Sydney is GMT+10, so London is 10 hours behind. 8:00 pm minus 10 hours equals 10:00 am the same day.
10
False
Large countries often span multiple time zones. Russia has 11 time zones and the USA has 6 (including territories). However, China uses only one time zone despite its size.