Earth & Space Science
You will learn how to use lines of latitude and longitude to locate positions on Earth.
After completing this tutorial, you will be able to complete the following:
Lines of latitude and longitude are used today without much thought. However, in the past, navigation was far more limited without these imaginary lines of reference. Before lines of latitude and longitude were used, sailors wishing to explore the vast seas had to rely on various methods, including looking at the position of the sun, moon, and stars. Winds and sea currents were also used, as were coastal landmarks, the compass, and sextant. However, sailors were usually limited by these early navigational tools. In fact, more accurate navigation was not possible until John Harrison, a carpenter and clockmaker, invented a measurement timepiece to calculate longitude.
Latitude and longitude are imaginary lines used for reference to help locate positions on the Earth. A latitude line, also known as a parallel, is an imaginary line that runs parallel to, and north or south of, the equator. The equator is the imaginary line that runs around the middle of the Earth. It splits the Earth into the Northern Hemisphere and Southern Hemisphere. The equator is used as the starting reference point of 0° latitude. A longitude line, also known as a meridian, is an imaginary line that runs from the North Pole to the South Pole.
The prime meridian is the arbitrary line of longitude that is used as the starting reference point of 0° longitude. It also splits the Earth into the Western Hemisphere and Eastern Hemisphere. The prime meridian was established by Sir George Airy in 1851, and adopted as the official prime meridian in 1884. It runs through the Royal Observatory, in Greenwich, England.
Lines of latitude and longitude are measured in degrees (°), and are noted by a directional compass letter, N, S, E, or W. Lines of longitude are perpendicular to lines of latitude, so they cross over, or intersect, whenever they meet. When locating a place on Earth, the intersection of a line of latitude and a line of longitude is used. To get a more accurate measurement of a location on Earth, degrees of latitude and longitude can be further divided into minutes (') and seconds ("). For each degree, there are 60 minutes, and each minute is divided into 60 seconds. Thus, a coordinate can be described in six digit terms, such as 27°58'48"N, 86°55'18"E for Mount Everest, Nepal.
Apart from using lines of latitude and longitude on maps or globes to locate positions, the Global Positioning System (GPS) can also be used. The Global Positioning System is a satellite-based navigational tool that triangulates latitude and longitude to locate a place on Earth. Though GPS was designed by the United States military, it is also used by civilians in a number of applications, including portable, interactive maps.
|Approximate Time||20 Minutes|
|Pre-requisite Concepts||Students should be familiar with these concepts: basic mathematics operations, equator, and prime meridian.|
|Course||Earth & Space Science|
|Type of Tutorial||Concept Development|
|Key Vocabulary||Earth coordinates, equator, Global Positioning System|