Globe: Latitudes and Longitudes
Overview
A globe is a small model of the Earth — we can draw lines on it to find the exact location of any place. These lines are called latitudes (horizontal lines) and longitudes (vertical lines). Using these lines, we can find out how warm a place will be and what the local time will be there.
Typed Notes
Globe — A Model of the Earth
A globe is a small, accurate model of the Earth — it shows oceans, continents, and everything else in the correct proportion. Inside the globe's needle, there is a rod that is slightly tilted — this shows the Earth's actual tilt (23½°). However, the problem with a globe is that you can see the entire Earth at once but cannot see a small area in detail. That is why maps are needed.
Latitudes — Horizontal Circular Lines
Latitudes are circular lines that go from the Equator towards the north and south. They are parallel to each other — they never meet, which is why they are also called 'parallels of latitude.' The Equator is at 0° latitude and divides the Earth into two equal halves — the Northern hemisphere and the Southern hemisphere. Going above the Equator, latitude increases from 0° to 90°N, and going below, it increases from 0° to 90°S. The North Pole is at 90°N and the South Pole is at 90°S.
Heat Zones — Divisions Based on Heat
The Sun's rays fall at different angles on different latitudes — because of this, the Earth is divided into three heat zones: (1) Torrid zone — between the Tropic of Cancer (23½°N) and the Tropic of Capricorn (23½°S); the Sun's rays fall directly here, making it the hottest zone. (2) Temperate zones — from the tropics to the circles; neither too hot nor too cold — the climate remains moderate. (3) Frigid zones — beyond the Arctic Circle (66½°N) and beyond the Antarctic Circle (66½°S); the Sun's rays fall at a slant here, so it remains freezing cold throughout the year.
Longitudes and the Calculation of Time
Longitudes are circular lines that join the North Pole to the South Pole — they are called meridians. They meet each other at the poles. The Prime Meridian (0°) passes through Greenwich (London) — it divides the Earth into the Eastern and Western hemispheres. The Earth rotates 360° in 24 hours, so 360° ÷ 24 = 15° — meaning every 15° difference in longitude equals 1 hour. Moving towards the east, time moves forward; moving towards the west, time moves backward. India is a very large country, so it has chosen its standard time from 82°30'E — this is called IST, which is 5 hours 30 minutes ahead of GMT.
Key Concepts
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- 01Latitude: Circular lines drawn from the Equator towards the north and south — they are parallel to each other (they never meet). The Equator (0°) divides the Earth into the Northern and Southern hemispheres.
- 02Important latitudes: Tropic of Cancer (23½°N), Tropic of Capricorn (23½°S), Arctic Circle (66½°N), Antarctic Circle (66½°S).
- 03Heat zones: Torrid zone (between the two tropics — hottest), Temperate zones (moderate climate), Frigid zones (beyond the circles — coldest).
- 04Longitude: Circular lines joining the North and South poles — called meridians. The Prime Meridian (0°) passes through Greenwich (London) and divides the Earth into the Eastern and Western hemispheres.
- 05Time: Every 15° difference in longitude = 1 hour. India takes its time from 82°30'E (Standard Meridian) — called IST, which is 5 hours 30 minutes ahead of GMT.
Questions & Solutions
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What is the Equator and what is its function?
What are the heat zones and where are they located?
Which longitude does India Standard Time (IST) come from, and how far ahead is it from GMT?
If two places have a difference of 30° in longitude, what will be the difference in their time?
What is the basic difference between latitudes and longitudes?
Why can't a globe serve every purpose — why is a map needed?
On a globe, latitudes (from 0° Equator towards N/S) indicate temperature zones, and longitudes (from 0° Greenwich towards E/W) indicate time. 15° of longitude = 1 hour. India's Standard Meridian is 82°30'E, from which IST is derived (GMT +5:30).
Chapter-end quiz
4 MCQsOption tap karo — turant pata chalega sahi ya galat, explanation ke saath.
Q1.Which place does the Prime Meridian pass through?
Q2.Where is the Torrid zone located?
Q3.How many degrees of longitude make a difference of 1 hour?
Q4.What is the position of the Arctic Circle?
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