What is a Globe?
A globe is a true model (miniature form) of the Earth. It shows continents, oceans, countries, and all features in their correct shape and relative size.
Axis and Poles
The Earth rotates on its imaginary axis that joins the North Pole and South Pole. The axis is tilted at 23.5°. The globe also has a needle (axis) passing through it.
Latitudes (Parallels)
All parallel circles from the Equator to the poles are called parallels of latitude.
• Equator (0°) – longest latitude
• Tropic of Cancer (23½° N)
• Tropic of Capricorn (23½° S)
• Arctic Circle (66½° N)
• Antarctic Circle (66½° S)
• North Pole (90° N), South Pole (90° S)
Heat Zones of the Earth
• Torrid Zone (between Tropics) – hottest
• Temperate Zones (between Tropic & Circle) – moderate
• Frigid Zones (beyond Circles) – coldest
Longitudes (Meridians)
Semi-circles running from pole to pole are called meridians of longitude.
• Prime Meridian (0°) passes through Greenwich
• 180° longitude is the International Date Line
• Total 360 longitudes (180° E + 180° W)
Longitude and Time
Earth rotates 360° in 24 hours → 15° in 1 hour → 1° in 4 minutes.
Local time differs by 4 minutes for every 1° of longitude.
Indian Standard Time (IST) = Time at 82½° E longitude.
UPSC/SSC One-Liners & Key Facts
- Equator = 0° latitude = longest parallel
- Total latitudes = 181 (90 N + 90 S + Equator)
- Total longitudes = 360
- Prime Meridian = 0° longitude = Greenwich
- India’s standard meridian = 82½° E
- Time difference: 1° longitude = 4 minutes
- India spans 68°E to 97°E → 29° difference → 1 hour 56 minutes time lag
- International Date Line = 180° longitude (zig-zag to avoid land)
- Tropic of Cancer passes through 8 Indian states
- India lies entirely in Northern & Eastern Hemisphere
Q1. What is a globe? Why is it the most accurate model of the Earth?
Answer: A globe is a spherical, three-dimensional, true model of the Earth. It is the most accurate because it shows continents, oceans, and countries in their correct shape, size, and position without any distortion (unlike flat maps).
Q2. Draw a neat diagram and explain important parallels of latitude.
Answer: (Students should draw Earth with axis and label)
• Equator (0°): Divides Earth into N & S hemispheres
• Tropic of Cancer (23½°N): Northern limit of direct sun rays
• Tropic of Capricorn (23½°S): Southern limit
• Arctic Circle (66½°N) & Antarctic Circle (66½°S): Limits of polar day/night
• Poles (90°N & 90°S)
Q3. Why does the Torrid Zone receive maximum heat?
Answer: The Torrid Zone lies between the Tropic of Cancer and Tropic of Capricorn. The midday sun is exactly overhead at least once a year on all latitudes in this zone, hence it receives the maximum amount of heat.
Q4. Explain the relationship between longitude and time with examples.
Answer: Earth rotates 360° in 24 hours → 15° per hour → 4 minutes per degree.
Example: When it is 12 noon at Greenwich (0°), it will be 12:04 pm at 1°E and 11:56 am at 1°W.
India’s extreme east-west difference is 29° → time difference of 1 hour 56 minutes (but we follow single IST).
Q5. Why has 82½° E been selected as the Standard Meridian of India?
Answer: It passes almost through the middle of India (near Allahabad). Using a central longitude avoids confusion of multiple time zones and ensures uniform time across the country.
Q6. What is the importance of the Prime Meridian and International Date Line?
Answer: Prime Meridian (0°) is the reference for measuring longitude and calculating world time (GMT/UTC). The 180° longitude (opposite to Prime Meridian) is the International Date Line. Crossing it westward adds a day, eastward subtracts a day.