Chapter Notes and Summary
• Globe is a true model of Earth.
• A needle is fixed through globe in a tilted manner, which is called its axis.
• imaginary line running on globe divides it into equal parts. This line is known as Equator.
• All parallel circles from Equator up to poles are called parallels of latitude. Latitude are measured in degree.
• As we move away from Equator, size of parallels of latitude decreases.
• four important parallels of latitude are :
• Tropic of Cancer (23½°N) l Tropic of Capricorn (23½°S) l Arctic of Circle (66½°N) l Antarctic Circle (66½°S)
• Heat Zones of Earth l Torrid zone receives, maximum heat.
• Temperate zone has moderate temperature.
• Frigid zone has cold climate as sun rays are always slanting.
• Longitudes l line of reference running from North Pole to South Pole are called Meridians of Longitude.
• distance between them are measured in ‘degrees of longitude’.
• All meridians are of equal length.
• meridian which passes through Greenwich, where British Royal Observatory is located is called Prime Meridian.
• value of Prime Meridian is 0° longitude and from it we count 180° Eastward as well as 180° Westward.
• Prime Meridian divides earth into two equal halves, Eastern Hemisphere and Western Hemisphere.
• 180° East and 180° West meridians are on same line.
• We can locate any point on globe if we know its latitude and longitude.
• Longitude and Time
• As earth rotates from West to East, those places East of Greenwich will be ahead of Greenwich time and those to West will be behind it.
• earth rotates 360° in about 24 hours.
• At any place a watch can be adjusted to read 12 o’clock when Sun is at highest point in sky.
• Standard Time
• local time various places are different so it is necessary to adopt local time of some central meridian of a country as Standard Time.
• 82½°E is treated as Standard Meridian of India. local time at this meridian is known as Indian Standard Time (IST).
• India located East of Greenwich at 82° 30’E, is 5 hours and 30 minutes ahead of GMT.
• Some countries have a great longitudinal extent and so they have adopted more than one standard time.