LATITUDE AND LONGITUDE

Notebook "Where are you?"

  

  

The lines of the Equator - zero latitude - and the parallels are shown on the globe. The parallels are circumference lines which run parallel to the circumference line of the Equator. Points of the globe along the same parallel have the same latitude.


Latitude is measured from the Equator so all points between the Equator and the North Pole are latitude north and all points between the Equator and the South Pole are latitude south.


The angle of the North Star above the horizon is the latitude of your location. Draw your latitude line on your globe.


15th and 16th century Portugueses navigators used the quadrant to find out their position on Earth. Every night, they measured the angle of the North Star above the horizon and noted their position on the globe they carried with them.


In this way, they never got lost on the seas and lands which had never been visited by other Europeans.


You have learnt to determine latitude on your globe. Similarly, you can draw imaginary circles around the globe which pass through the North Pole and the South Pole. These circles which pass through both poles are called the Earth’s meridians. The longitude of a position is the number of degrees between the Greenwich Meridian and this location, which can be either to the east or to the west.


E.g. When you see the North Star from any point along the 20ºN line of latitude, the angle of the North Star above the horizon is 20º. The longitudinal scale is marked along the line of the Equator!

Activity


On your globe you can see one scale along the line of the Equator and another along the Greenwich Meridian. These scales are the same as the scales on your protractor.


  • Choose and mark a Portuguese city on your globe. See if its longitude is east or west of the Greenwich meridian.
    To determine the latitude and longitude of a location on Earth, you just follow the parallel and the meridian which pass through this city and look at the values on the scales drawn along the Equator and the Greenwich Meridian. Latitude and longitude figures are the degrees travelled from the Equator and the Greenwich Meridian to the point you have chosen.

  • Latitude:___________________________Longitude:__________________________
    Now if you compare this latitude with the angle of the North Star above the horizon, you will see that the two figures are almost exactly the same!