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Latitude and longitude Latitude and longitude are imaginary (unreal) lines drawn on maps to easily locate places on the Earth. Latitude is distance north or south of the equator (an imaginary circle around the Earth halfway between the North Pole and the South Pole). One degree of latitude covers about 69 miles (111 kilometers).
Transcript of The Tropic of Cancer and The Tropic of Capricorn€¦ · Web viewThe Tropic of Capricorn lies at...
Latitude and longitude
Latitude and longitude are imaginary (unreal) lines drawn on maps to
easily locate places on the Earth.
Latitude is distance north or south of the equator (an imaginary circle around the Earth halfway between the North Pole and the South Pole). One degree of latitude covers about 69 miles (111 kilometers).
Longitude is measured in degrees east or west of the prime meridian. This means one half of the world is measured in degrees of
east longitude up to 180°, and the other half in degrees of west longitude up to 180°.
Equator
The Equator is the line of 0° latitudes, the starting point for measuring
latitude. The latitude of the North Pole is 90° N, and that of the South
Pole is 90° S. The latitude of every point in between must be some
degree north or south, from 0° to 90°.
Prime meridian
Prime Meridian is an imaginary line that, similar to the Equator,
divides the earth into eastern and western hemispheres. This meridian
passes through the Royal Observatory in Greenwich, England and
sometimes it is referred to as the Greenwich Meridian.
History of the Prime MeridianLet's take a look at the history of the Prime Meridian, beginning in the 1800's. At the time, railroads had become a major mode of transportation in the United States and Canada. In 1883, the two nations established a standard time system for North America to make
railroad travel more dependable. It was rather successful and in October 1884, the International Meridian Conference in Washington DC was held so that a global standardized time system could be established.
Part of the challenge in establishing a global time system was deciding where it's starting point would be. While the Equator is obviously the starting point for lines of latitude, the Prime Meridian's location had to be chosen. At the time of the conference, each country had their own line of longitude that they considered to be the meridian line, or starting line from which longitude was measured. After lots of debate, the meridian that passes through the Royal Observatory in Greenwich, England, was chosen. The reason was simple and practical: over 43 of the world's shipping lines used it as a navigational base.
See the diagrams to understand latitudes and
longitudes.
The Tropic of Cancer and The Tropic of Capricorn
The Tropic of Cancer and the Tropic of Capricorn each lie at 23.5
degrees latitude.
Tropic of Cancer
The Tropic of Cancer is located at 23.5° North of the equator and runs
through Mexico, the Bahamas, Egypt, Saudi Arabia, India, and southern
China.
The sun is directly overhead at noon on the Tropic of Cancer on June
21 (the beginning of summer in the Northern Hemisphere and the
beginning of winter in the Southern Hemisphere)
Tropic of Capricorn
The Tropic of Capricorn lies at 23.5° South of the equator and runs through Australia, Chile, southern Brazil (Brazil is the only country that passes through both the equator and a tropic), and northern South Africa. The sun is directly overhead at noon on the Tropic of Capricorn on December 21 (the beginning of winter in the Northern Hemisphere and the beginning of summer in the Southern
******** The reason for the location of the Tropic of Cancer and
the Tropic of Capricorn at 23.5° north and south respectively is
due to the axial tilt of the Earth. The Earth is titled 23.5
degrees from the plane of the Earth's revolution around the
sun each year.
Where Do the Prime Meridian and the Equator Intersect?
- The Gulf of Guinea, just off the western coast of Africa.
Standard TimeStandard Time, the time of a region or country that is established by
law or general usage as civil time.
The concept was adopted in the late 19th century in an attempt to end
the confusion that was caused by each community’s use of its own
solar time. Some such standard became increasingly necessary with
the development of rapid railway transportation and the consequent
confusion of schedules that used scores of different local times kept in
separate communities. (Local time varies continuously with change in
longitude.) The need for a standard time was felt most particularly in
the United States and Canada, where long-distance railway routes
passed through places that differed by several hours in local time. Sir
Sandford Fleming, a Canadian railway planner and engineer, outlined a
plan for worldwide standard time in the late 1870s. Following this
initiative, in 1884 delegates from 27 countries met in Washington,
D.C., and agreed on a system basically the same as that now in use.
The present system employs 24 standard meridians of longitude (lines
running from the North Pole to the South Pole, at right angles to the
Equator) 15° apart, starting with the prime meridian through
Greenwich, England. These meridians are theoretically the centers of
24 Standard Time zones, although in practice the zones often are
subdivided or altered in shape for the convenience of inhabitants; a
notable example of such alteration is the eastward extension of the
International Date Line around the Pacific island country of Kiribati.
Time is the same throughout each zone and differs from the
international basis of legal and scientific time, Coordinated Universal
Time, by an integral number of hours; minutes and seconds are the
same. In a few regions, however, the legal time kept is not that of one
of the 24 Standard Time zones, because half-hour or quarter-hour
differences are in effect there. In addition, Daylight Saving Time is a
common system by which time is advanced one hour from Standard
Time, typically to extend daylight hours during conventional waking
time and in most cases for part of the year (usually in summer).
Map of world time zones. Encyclopædia Britannica, Inc.
• Why do we need time zones?• Are the time zones related to latitude and longitude?• How many degrees complete a rotation of the Earth?• How many time zones are there in the world?• How many time zones are there in Canada?• What time difference generally exists between two adjacent time zones?• Is it earlier or later as you travel west? East?• Where is the dividing line between east and west longitude?• Is it the same date everywhere in the world?
Equator• North Pole• South Pole• Prime Meridian• Tropic of Cancer• Tropic of Capricorn• Arctic Circle• Antarctic Circle• Prime Meridian
• International Date Line
