9
0º
15º
30º
45º
60º
75º
90º
105º
120º
135º
150º
165º
180º
15º
30º
45º
60º
75º
90º
105º
120º
135º
150º
12:00 +1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+11
+12
–
1
–
2
–
3
–
4
–
5
–
6
–
7
–
8
–
9
–
10
–
12
–
11
–
11
+1
+1
+2
+2
+2
+2
+3
+3
+3
+3
+3:30
+4
+4
+4:30
+5:30
+5
+6
+7
+9
+8
+10
+11
+12
+9
+11
+10
+7
+8
+9:30
+8:45
+12
0
–
3
–
4
–
5
–
4:30
–
4
–
5
–
6
–
7
–
8
–
9
–
10
–
3
0
–
3:30
+10:30
+11
International Date Line
165º
!
1
20
Important
When it’s 12 p.m. at the prime
meridian (0° longitude), on
the opposite side of the Earth
at the 180th meridian (180°
longitude), it’s 12 a.m. The
180th meridian in the Pacific
Ocean coincides with the
International Date Line
.
5. TIME ZONES
The extent in degrees of each time zone is determined in this way: The Earth’s sphere
has 360°. This is divided into the number of hours the Earth planet takes to complete
one rotation (360° divided by 24 hours = 15°). So, each hour is equal to 15° of
longitude.
The prime meridian or Greenwich meridian is the starting point for the time zones
around the world. It is called
GMT
10
. If you travel east from this point you add an hour
for every time zone you cross; but if you travel west, you subtract an hour for each
time zone (or 15° of longitude).
Time zones are mainly used to establish the time difference between different regions
and countries of the Earth.
The Earth takes
24 hours
to complete one rotation on its axis. Each of these hours
is represented by a vertical strip called a
time zone
.
10
GMT:
abbreviation of Greenwich
Mean Time
Apply
27.
Think of two places: one is at 60° W; the other at 150° E. If it is 10 a.m.
in Greenwich, what time is it in these two places?
28.
Look at the world time zone map and respond.
❚
Which Spanish autonomous community is in a different time zone from
the rest?
❚
What time would it be in this autonomous community if were 12 p.m. on the
Iberian Peninsula?
Evaluate
29.
Look on the Internet and find
out why the majority of the
countries in the European Union
decided to adopt the same
official time, even though they
are in different time zones.
