2. Unit 21: Finding the location and time of our destinations (A)What are latitudes and longitudes ? Latitudes and longitudes  Are north-south and east-west imaginary lines drawn on the earth’s surface  Are similar to grid lines  Are measured in degrees (1 degree = 60 minutes; 1 minute = 60 seconds)  Show the absolute location of a place on the earth Next

3. Unit 21: Finding the location and time of our destinations Latitudes For examples: The latitude of Hong Kong is 22  N and Sydney is 33  S.  Are numbered in degrees from 0 to 90  The equator is latitude 0  - the longest latitude which divides the earth into Northern Hemisphere and Southern Hemisphere.  A place north of the equator is marked a number of degree north; whereas a place south of the equator is marked a number of degree south.  The North Pole and South Pole are 90°N and 90°S.  Are imaginary lines running parallel from west to east around the earth Next

4. Unit 21: Finding the location and time of our destinations Longitudes  Are imaginary lines running from north to south which join the two poles  Are also called meridians  The meridian passing through Greenwich near London is the Prime Meridian. For examples: Hong Kong is 114  E and New York is 76  W.  All longitudes to the Greenwich meridian’s east are marked east; whereas those to the Greenwich meridian’s west are marked west  180  E and 180  W are in fact the same line, so it is just called 180 . Next

5. Unit 21: Finding the location and time of our destinations (B)How do we find the latitude and longitude of a place from an atlas ? Suppose we want to find the location of Guangzhou in an atlas:  We should look for the place in the index  We may have the following information: Guangzhou23 5N113 10E 28 LatitudeLongitudePage  The last number is the page on which you can find a map showing Guangzhou.  When you turn to page 28 in the atlas, you can find the location of Guangzhou. Next

6. Unit 21: Finding the location and time of our destinations (C)How do we find the local time and standard time of our destinations ? Using longitudes to work out the time of different parts of the world  There are 360  of longitude  The earth rotates on its axis from west to east. It takes 24 hours to complete one rotation.  This means the earth takes 4 minutes to rotate by 1  of longitude and one hour to rotate by 15 .  We can use longitudes to work out the time of different places.  Hong Kong is on 114  E. If our time is 8 a.m., then the place on 129  E should be one hour ahead of us, i.e. 9a.m. whereas the place on 99  E should be one hour behind us, i.e. 7 a.m. Next

7. Unit 21: Finding the location and time of our destinations Local time  Is worked out based on the longitude of the place  For every 1  of longitude east of Hong Kong, the local time will be 4 minutes ahead of our local time  Likewise, for every 1  of longitude west of Hong Kong, the local time will be 4 minutes behind our local time Next

8. Unit 21: Finding the location and time of our destinations Standard time  If every place sticks to its local time, it will be very confusing.  In order to solve this problem, the earth is divided into 24 time zones.  Each time zone covers 15 degrees of longitudes.  There is a difference of one hour between one time zone and the next.  All the places within the same time zone have the same standard time. Next  Big countries like China cannot give one single time because they extend a large number of longitudes.

9. Unit 21: Finding the location and time of our destinations Examples: Hong Kong lies in the Standard Time Zone of 120°E; whereas London lies in that of 0°. Therefore, the Standard Time of Hong Kong is 8 hours ahead of London. Next

10. Unit 21: Finding the location and time of our destinations Terms to learn:  Latitude - an imaginary line running across the world from west to east  Longitude/meridian - an imaginary line running from north to south joining the two poles  The Prime meridian - the 0° longitude passing through Greenwich near London. It is also called the Greenwich meridian. End

11. Unit 21: Finding the location and time of our destinations Latitudes Back

12. Unit 21: Finding the location and time of our destinations Longitudes Back

13. Unit 21: Finding the location and time of our destinations Standard time Back