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Geography: Time zones
I can talk about time zones.
1. Check the meanings of the words in the box. Read the text and match the words to numbers 1-7 on the map.
| longitude Prime Meridian Greenwich Mean Time east west north south |
Time zones
Time zones help us know what time it is in different parts of the world. This is because when the Earth rotates, the sun shines on only one part of the Earth, so when it's the morning in your country, it's night-time in another country.
The Earth has got twenty-four time zones. The lines for each time zone go from north to south. These are called lines of longitude. The line on the map at 0° longitude is called the Prime Meridian. This line goes through Greenwich, in London. The time there is called Greenwich Mean Time (GMT).
The Earth rotates 15° of longitude every hour (24 x 15° = 360°). Places east of the Prime Meridian are ahead of GMT. For example, Istanbul is about 30° east of the Prime Meridian, so the time there is GMT plus two hours. Places west of the Prime Meridian are ahead of GMT. For example, Istanbul is about 30° east of the Prime Meridian, so the time there is GMT plus two hours. Places west of the Prime Meridian are behind GMT. For example, Rio is about 45° west of the Prime Meridian, so the time there is GMT minus three hours. So when it is 12 p.m. in London, it is 2 p.m. in Istanbul and 9 a.m. in Rio.
2. 🎧1.26 Read and listen to the text and write True or False. Correct the false sentences.
1. Lines of longitude go from east to west.
2. The Prime Meridian is the name of a time zone.
3. Greenwich is a part of London.
4. The time in places west of the Prime Meridian is ahead of GMT.
3. Look at the clocks and answer the questions.
1. London 2. New York 3. Madrid
4. Brasilia 5. Brisbane 6. Hà Nội
1. In which countries are cities 1-6?
2. Is New York ahead of or behind GMT?
3. How many hours ahead of GMT is Hà Nội?
4. How many hours behind GMT is Brasilia?
5. If it's 12 p.m. in London, what time is it in Brisbane?
6. You are in New York at 9 p.m. Is it a good idea to call your friend in London? Why / Why not?
4. 
USE IT! Work in pairs. Complete the table. Then ask and answer questions about the time in the different cities.
| City | GMT +/- | Time |
| London | - | 1 p.m. |
| Tokyo | +9 hours | |
| Mexico City | 8 a.m. | |
| Sydney | 11 p.m. | |
| Rio | - 3 hours | |
| Hà Nội | +7 hours |
Hi! I'm in London. Where are you?
I'm in Hà Nội.
It's 1 p.m. in London. What's the time in Hà Nội?
It's 8 p.m.
