Chapter 3: The Globe - A Model of the Earth
🌍 Complete Chapter for PSTET Paper II (Social Studies)
🎯 Learning Objectives for PSTET Aspirants
After completing this chapter, you will be able to:
Define a globe and explain its advantages and limitations as a model of Earth
Understand the grid system formed by latitudes and longitudes
Locate places on Earth using coordinates
Identify and explain the three heat zones of the Earth
Apply pedagogical strategies to teach globe concepts effectively
Guide students in using atlases and developing map skills
3.1 What is a Globe? Its Advantages and Limitations as a Model
🌐 Definition of a Globe
A globe is a spherical model of Earth that represents the planet's shape, surface features, and spatial relationships accurately . It is the most accurate representation of Earth because it maintains the true spherical shape of our planet.
| Aspect | Description |
|---|---|
| Shape | Perfect sphere (though Earth is slightly oblate) |
| Purpose | To show Earth's surface without distortion |
| Scale | True to scale in all directions |
| Features | Shows continents, oceans, countries, and grid lines |
💡 Key Insight: The word "globe" comes from the Latin word globus, meaning "sphere" or "round mass."
✅ Advantages of Using a Globe
❌ Limitations of a Globe
📝 PSTET Focus Point: Questions often ask about the advantages and disadvantages of using a globe versus a map. Remember that globes are accurate but impractical for detailed study, while maps are portable but distorted .
🔍 Types of Globes
📐 Globe Mountings
3.2 The Grid System: Understanding How Latitudes and Longitudes Form a Grid
🗺️ What is the Grid System?
The geographic grid system is a network of imaginary lines—parallels of latitude and meridians of longitude—that cover the globe, enabling us to locate any point on Earth's surface precisely .
NORTH POLE (90°N)
▲
│
│
┌────────────────────┼────────────────────┐
│ │ │
│ MERIDIANS │ PARALLELS │
│ (Longitudes) │ (Latitudes) │
│ │ │
│ Run N-S │ Run E-W │
│ Meet at poles │ Parallel │
│ │ Never meet │
└────────────────────┼────────────────────┘
│
│
▼
SOUTH POLE (90°S)📊 Comparison: Latitudes vs. Longitudes
🔢 Understanding Latitude
Latitude is the angular distance of a point north or south of the equator, measured in degrees .
| Latitude Fact | Detail |
|---|---|
| Measurement | Angle from equator to point, measured at Earth's center |
| Symbol | Greek letter φ (phi) |
| Range | 0° at equator to 90° at poles |
| Hemispheres | Northern (N) and Southern (S) |
| Important Parallels | Equator (0°), Tropics (23.5°), Arctic/Antarctic Circles (66.5°) |
📏 Understanding Longitude
Longitude is the angular distance of a point east or west of the Prime Meridian, measured in degrees .
🎯 How the Grid Works Together
When we combine latitudes and longitudes, we create a coordinate system where every location on Earth has a unique address .
┌─────────────────┐
│ (75°E, 30°N) │
│ ● │
│ Location in │
│ Northwest │
│ India │
└─────────────────┘Examples of Coordinates:
📐 Great Circles and Small Circles
✈️ Important Application: The shortest distance between two points on Earth is along a great circle path, which is why flight routes appear curved on flat maps .
🕰️ Relationship with Time
The grid system is also fundamental to understanding time zones:
Earth rotates 360° in 24 hours
1° of longitude = 4 minutes time difference
3.3 Finding Locations: Practical Exercises on Finding Places Using Coordinates
🔍 Understanding Coordinate Formats
Coordinates can be expressed in different formats :
📝 Step-by-Step Guide to Finding Locations
Step 1: Identify the Coordinates
Latitude always comes first (north-south position)
Example: "20°N, 80°E" means 20 degrees North latitude, 80 degrees East longitude
Step 2: Locate the Latitude
Find the parallel line closest to the given latitude
If latitude is North, move upward from equator
If latitude is South, move downward from equator
Step 3: Locate the Longitude
Find the meridian closest to the given longitude
If longitude is East, move right from Prime Meridian
If longitude is West, move left from Prime Meridian
Step 4: Find the Intersection
Where the latitude parallel and longitude meridian cross is your location
🧩 Practice Exercises for Students
Exercise 1: Basic Coordinates
Find these locations on a globe or atlas:
| Coordinates | Location | Answer |
|---|---|---|
| 28°N, 77°E | ? | New Delhi, India |
| 19°N, 73°E | ? | Mumbai, India |
| 13°N, 80°E | ? | Chennai, India |
| 22°N, 88°E | ? | Kolkata, India |
| 52°N, 0° | ? | London, UK |
| 35°N, 135°E | ? | Tokyo, Japan |
| 41°S, 175°E | ? | Wellington, New Zealand |
Exercise 2: Find the Coordinates
For these famous locations, find the approximate coordinates:
| Location | Latitude | Longitude |
|---|---|---|
| Taj Mahal, Agra | 27°10'N | 78°02'E |
| Gateway of India, Mumbai | 18°55'N | 72°50'E |
| India Gate, New Delhi | 28°36'N | 77°13'E |
| Eiffel Tower, Paris | 48°51'N | 2°17'E |
| Statue of Liberty, New York | 40°41'N | 74°02'W |
| Sydney Opera House | 33°51'S | 151°12'E |
Exercise 3: Which is Farther North?
Compare these pairs and identify the more northern location:
| Pair | Comparison | Answer |
|---|---|---|
| 40°N or 20°N | Higher latitude = farther north | 40°N |
| 15°S or 30°N | Northern hemisphere vs Southern | 30°N |
| 45°N or 45°S | Northern vs Southern | 45°N |
Exercise 4: Which is Farther East?
(Assuming Prime Meridian as reference, East positive)
| Pair | Comparison | Answer |
|---|---|---|
| 80°E or 100°E | Higher east longitude = farther east | 100°E |
| 20°W or 10°E | West vs East | 10°E |
| 170°E or 170°W | Near International Date Line | 170°E |
🎮 Fun Classroom Activities
Activity 1: "Find My Location" Game
Teacher provides coordinates
Students race to find the location on globe/atlas
First student to correctly identify the place wins
Activity 2: "Mystery Coordinates"
Give students coordinates of a famous place
They must identify the place using clues from the location
Example: "28°N, 77°E" → New Delhi → Capital of India
Activity 3: "Coordinate Bingo"
Create bingo cards with coordinates
Call out place names
Students mark coordinates where those places are located
Activity 4: "Where in the World?"
Students choose a secret location
Give classmates latitude and longitude clues
Others try to guess the location
📱 Using Technology for Location Finding
Modern tools make location finding interactive :
💡 Teaching Tip: When using technology, ensure students understand the underlying concept—technology should enhance, not replace, fundamental understanding.
3.4 Heat Zones of the Earth: Torrid, Temperate, and Frigid Zones
☀️ What Determines Heat Zones?
The Earth's heat zones are primarily determined by:
Insolation (incoming solar radiation) received at different latitudes
Angle of sun's rays (vertical vs. slanting)
🌡️ The Three Heat Zones
Based on latitude and the amount of heat received, Earth is divided into three major heat zones :
NORTH POLE (90°N)
│
FRIGID ZONE (90°N - 66.5°N)
│
ARCTIC CIRCLE (66.5°N)
│
TEMPERATE ZONE (66.5°N - 23.5°N)
│
TROPIC OF CANCER (23.5°N)
│
TORRID ZONE (23.5°N - 23.5°S)
│
TROPIC OF CAPRICORN (23.5°S)
│
TEMPERATE ZONE (23.5°S - 66.5°S)
│
ANTARCTIC CIRCLE (66.5°S)
│
FRIGID ZONE (66.5°S - 90°S)
│
SOUTH POLE (90°S)🔥 Torrid Zone (Tropical Zone)
Special Feature: The sun is directly overhead at least once a year at all places in this zone.
🌿 Temperate Zones
Four Distinct Seasons: Spring, Summer, Autumn, Winter are clearly experienced in most parts.
❄️ Frigid Zones
Midnight Sun Phenomenon: In summer, sun never sets for several weeks; in winter, sun never rises.
📊 Comparison of Heat Zones
🌍 Isotherms and Heat Zones
Isotherms are imaginary lines joining places having equal temperatures .
📝 PSTET Focus Point: The thermal equator (line of highest temperatures) lies south of the geographical equator due to greater landmass in Northern Hemisphere .
3.5 Pedagogical Focus: Hands-on Activities with Globes; Teaching Students to Use an Atlas
🧒 Understanding the Learner (Classes VI-VIII)
Upper primary students:
Are concrete thinkers moving toward abstract thinking
Learn best through hands-on, experiential activities
Need visual aids to understand spatial concepts
Benefit from structured practice with maps and globes
💡 Creating a Geography-Rich Classroom
A geography-rich classroom immerses students in geographic learning through multiple resources and activities .
👐 Hands-On Globe Activities
Activity 1: "String the Globe" - Finding Great Circle Routes
| Aspect | Detail |
|---|---|
| Objective | Understand shortest distance between two points |
| Materials | Globe, string, markers |
| Procedure | 1. Mark two cities (e.g., New York and London) 2. Stretch string tightly between them 3. Observe path—it's a curve! 4. Trace path on globe with marker |
| Discussion | Why do airplanes fly curved paths? Why is this route shorter than straight line on flat map? |
Activity 2: "Day and Night on Globe"
Activity 3: "Seasons on a Tilted Globe"
Activity 4: "Latitude and Longitude Hunt"
Activity 5: "Comparing Globes and Maps"
📘 Teaching Students to Use an Atlas
An atlas is a collection of maps, tables, and charts that provides systematic geographic information .
Parts of an Atlas
Step-by-Step Atlas Skills
Step 1: Find a Place Using Index
Look up place name in alphabetical index
Note the page number
Note the grid reference (e.g., B3, D4)
Turn to that page
Find the grid square using letters and numbers
Step 2: Use Coordinates
Find place in index
Note latitude and longitude
Locate those coordinates on map
Step 3: Read Map Symbols
Check legend for symbol meanings
Identify features (roads, rivers, cities, boundaries)
Use colors to understand elevations/climate
Step 4: Use Scale
Find scale bar
Measure distance on map
Calculate actual distance using scale
📋 Progressive Atlas Skills by Class Level
🎮 Fun Atlas Activities
Activity 1: "Atlas Scavenger Hunt"
| Question | Answer Location |
|---|---|
| What is the capital of Peru? | Index → Peru → Page reference |
| Which river flows through Cairo? | Egypt map → Nile River |
| What is the population of Japan? | Statistical tables |
| Which countries border Germany? | Europe map |
| What is the highest mountain in Africa? | Physical map of Africa → Kilimanjaro |
Activity 2: "Mystery Country"
Give clues about a country (continent, bordering countries, capital, physical features)
Students use atlas to identify the country
Activity 3: "Where in the World Am I?"
Give coordinates of a famous place
Students find place and identify what makes it famous
Activity 4: "Map Your Neighborhood"
🌐 Integrating Technology with Atlas Skills
💡 Teaching Tip: Combine traditional atlas skills with technology. Students should know how to use both print and digital resources effectively.
📝 Common Student Misconceptions and How to Address Them
📝 Chapter Summary: Key Points for PSTET Revision
🔑 The Globe
Advantages: No distortion, correct shapes and sizes, shows Earth's curvature
Limitations: Not portable, cannot show details, expensive, only half visible
🔑 Grid System
Small circles: Plane does not pass through center
🔑 Finding Locations
Formats: DMS, decimal degrees, degrees-decimal minutes
🔑 Heat Zones
| Zone | Location | Characteristics |
|---|---|---|
| Torrid | 23.5°N - 23.5°S | Vertical rays, hottest |
| Temperate | 23.5° - 66.5° N and S | Slanting rays, moderate |
| Frigid | 66.5° - 90° N and S | Very slanting rays, coldest |
🔑 Pedagogical Focus
Use hands-on activities with globes
Address common misconceptions directly
Integrate technology thoughtfully
📝 Practice Questions for PSTET Preparation
Multiple Choice Questions
Which of the following is the most accurate representation of Earth?
a) Mercator map
b) Robinson projection map
c) Globe
d) Topographic mapThe Prime Meridian passes through which observatory?
a) Paris Observatory
b) Royal Observatory, Greenwich
c) Mount Palomar Observatory
d) Arecibo ObservatoryThe Tropic of Cancer is located at:
a) 0° latitude
b) 23.5° North latitude
c) 66.5° North latitude
d) 90° North latitudeWhich heat zone receives maximum insolation?
a) Frigid Zone
b) Temperate Zone
c) Torrid Zone
d) All receive equal insolationLines of longitude are also called:
a) Parallels
b) Meridians
c) Equators
d) TropicsThe range of latitudes is:
a) 0° to 180° E and W
b) 0° to 90° N and S
c) 0° to 360°
d) -180° to +180°Which of the following is a limitation of a globe?
a) It distorts shapes
b) Only half can be seen at once
c) Directions are incorrect
d) Distances cannot be measuredThe Arctic Circle is located in which heat zone?
a) Torrid Zone
b) Temperate Zone
c) Frigid Zone
d) Boundary between Temperate and FrigidIn the index of an atlas, what information is typically provided?
a) Only the page number
b) Page number and coordinates
c) Only the country name
d) Population data onlyThe shortest distance between two points on Earth is along:
a) A parallel of latitude
b) A meridian of longitude
c) A great circle
d) The equator always
Short Answer Questions
List three advantages and three limitations of using a globe to study Earth.
Differentiate between latitudes and longitudes with at least four points of comparison.
Explain the three heat zones of Earth with their latitudinal extents and characteristics.
How would you find a location on a globe if you are given its coordinates?
Describe three hands-on activities for teaching globe concepts to Class VI students.
Long Answer Questions
"The globe is the most accurate representation of Earth, yet maps are more commonly used." Explain this statement with reference to the advantages and limitations of globes.
Describe the grid system formed by latitudes and longitudes. How does this system help in locating places on Earth? Provide examples.
Explain the factors that determine the heat zones of Earth. Why is the Torrid Zone hotter than the Frigid Zone?
As a teacher, how would you design a progressive atlas-skills curriculum for Classes VI, VII, and VIII? Describe specific activities for each level.
Discuss the importance of using globes in geography education. What common misconceptions about Earth's features can be addressed through globe-based activities?
✅ Chapter Completion Checklist
Before moving to Chapter 4, ensure you can:
Define a globe and explain its purpose
Name the important parallels of latitude
Locate places using coordinates
Explain why Torrid Zone is hottest and Frigid Zone coldest
Plan 3 hands-on activities for teaching with globes
Identify and address 5 common student misconceptions
🔗 Online Resources for Further Learning
| Resource | Description | Link/How to Find |
|---|---|---|
| Google Earth | Virtual globe for exploration | earth.google.com |
| National Geographic Education | Geography teaching resources | education.nationalgeographic.org |
| NCERT Geography Textbooks | Class VI, VII, VIII resources | ncert.nic.in |
| Time and Date Website | Latitude/longitude tools | timeanddate.com |
| GIS for Schools | Interactive mapping | esri.in/en-in/industries/education/programs/schools |
| Oxford Atlas Resources | Atlas teaching materials | oup.com.au/primary/oxford-atlas |
🎓 Prepared for PSTET Aspirants
This chapter provides comprehensive coverage of "The Globe - A Model of the Earth" as per PSTET Paper II syllabus. The globe is your window to understanding Earth's spatial relationships—master it thoroughly for both the exam and your future teaching career!
