The Globe:

1. The globe is a miniature model of the Earth.
2. It helps us understand the shape, location, and position of continents, oceans, and countries.
3. A globe is useful for studying Earth but has limitations as it cannot show detailed information like maps.

Axis and Poles:

1. The Earth rotates on an imaginary line called the axis, which passes through the North Pole and South Pole.
2. North Pole: The northernmost point of the Earth.
3. South Pole: The southernmost point of the Earth.

Equator:

1. The Equator is an imaginary line dividing the Earth into two equal halves:
   a. Northern Hemisphere (above the equator).
   b. Southern Hemisphere (below the equator).
2. The Equator is at 0° latitude.

Latitudes:

1. Latitudes are imaginary lines that run parallel to the Equator.
2. They are measured in degrees from 0° at the Equator to 90° at the poles.
3. Lines of latitude are parallel to each other.
4. The distance between two latitudes is always the same.
5. A place at 20° N latitude is 20 degrees north of the Equator.
6. A place at 45° S latitude is 45 degrees south of the Equator.
7. Important Latitudes and Their Features:
   1. Equator (0°): Divides Earth into Northern and Southern Hemispheres.
   2. Tropic of Cancer (23½° N): Found in the Northern Hemisphere.
   3. Tropic of Capricorn (23½° S): Found in the Southern Hemisphere.
   4. Arctic Circle (66½° N): Near the North Pole.
   5. Antarctic Circle (66½° S): Near the South Pole.

Longitudes:

1. Longitudes are imaginary lines that run from the North Pole to the South Pole.
2. They are also called meridians.
3. Longitudes are measured up to 180° east and 180° west.
4. A place at 30° E longitude is 30 degrees east of the Prime Meridian.
5. A place at 120° W longitude is 120 degrees west of the Prime Meridian.
6. The Prime Meridian divides the Earth into two halves:
   
   a. The Eastern Hemisphere (from 0° to 180° E).
   b. The Western Hemisphere (from 0° to 180° W).

Combined Use of Latitudes and Longitudes (Grid):

1. The network of latitudes and longitudes forms a grid.
2. This grid helps us locate any place on Earth with a specific latitude and longitude.
   Example: Delhi is located at 28° N (latitude) and 77° E (longitude).
3. The location 28° N, 77° E refers to a place that is:
   
   a. 28 degrees north of the Equator.
   b. 77 degrees east of the Prime Meridian.
   c. This is the location of Delhi, India.

Heat Zones of the Earth:

Based on the latitudes, Earth is divided into three heat zones:

1. Torrid Zone (Hot Zone):
   1. Located between the Tropic of Cancer and the Tropic of Capricorn.
   2. Receives direct sunlight and is the hottest region.
2. Temperate Zones (Moderate Zone):
   1. Found between the Tropic of Cancer and the Arctic Circle (North) and the Tropic of Capricorn and the Antarctic Circle (South).
   2. Sunlight is moderate, neither too hot nor too cold.
3. Frigid Zones (Cold Zone):
   1. Found near the poles, beyond the Arctic Circle and Antarctic Circle.
   2. Receives very little sunlight and is the coldest region.

Time and Longitudes:

1. The Earth rotates 360° in 24 hours, so it rotates 15° in 1 hour.
2. Time Zones
   1. Every 15° longitude represents a difference of 1 hour.
   2. GMT is the standard time which is set at 0° longitude.
   3. Places to the east of the Prime Meridian are ahead of Greenwich Mean Time (GMT), and those to the west are behind GMT.
3. Indian Standard Time (IST)
   1. The standard meridian of India is 82½° E.
   2. IST is 5 hours 30 minutes ahead of GMT.

Greenwich Mean Time (GMT)

Greenwich Mean Time (GMT) is the time measured at the Prime Meridian (0° longitude), which passes through Greenwich, a town near London in the United Kingdom. It serves as the base reference time for calculating time across the world.

1. Prime Meridian and GMT:
   1. The Prime Meridian is the imaginary line that divides the Earth into the Eastern and Western Hemispheres.
   2. GMT is the standard time at this meridian, which is set at 0° longitude.
2. Global Time Standard:
   1. GMT was historically used as the world’s standard time zone.
   2. It forms the basis for the system of time zones, where local times are calculated by adding or subtracting hours from GMT.
3. 1. The Earth rotates 360° in 24 hours, so it rotates 15° longitude per hour.
   2. Locations to the east of the Prime Meridian are ahead of GMT, and those to the west are behind GMT.
4. Time Zones and Offsets:
   1. Time zones are denoted as GMT+X (hours ahead of GMT) or GMT-X (hours behind GMT).
      Example:
      a. India follows GMT+5:30.
      b. New York follows GMT-5.
5. Relation to UTC:
   1. GMT has been largely replaced by Coordinated Universal Time (UTC) in scientific and precise timekeeping.
   2. However, GMT is still commonly used in navigation, aviation, and informal contexts.
6. Example of GMT Usage:
   1. If it is 12:00 noon GMT, the local time in different cities would be:
      
      a. New York (GMT-5): 7:00 AM.
      b. London (GMT+0): 12:00 PM (same as GMT).
      c. Delhi (GMT+5:30): 5:30 PM.
      d. Tokyo (GMT+9): 9:00 PM.