Chapter 2 – The Earth – Our World (Full Concept Notes)
1. Earth (पृथ्वी)
Definition (English)
The Earth is the third planet from the Sun. It is the only known planet that supports life because it has air, water, and land.
Example
Earth has plants, animals, and human beings.
परिभाषा (Hindi)
पृथ्वी सूर्य से तीसरा ग्रह है। यह एकमात्र ज्ञात ग्रह है जहाँ वायु, जल और भूमि होने के कारण जीवन संभव है।
उदाहरण
पृथ्वी पर मनुष्य, पशु-पक्षी और पेड़-पौधे रहते हैं।
Important Points
Third planet from the Sun.
Supports life.
Has land and water.
Rotates on its axis.
Revolves around the Sun.
हिंदी में मुख्य बिंदु
सूर्य से तीसरा ग्रह।
जीवन वाला ग्रह।
भूमि और जल दोनों हैं।
अपनी धुरी पर घूमती है।
सूर्य की परिक्रमा करती है।
2. Solar System (सौरमंडल)
Definition (English)
The Solar System is made up of the Sun and eight planets that revolve around it.
Example
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
परिभाषा (Hindi)
सौरमंडल सूर्य तथा उसके चारों ओर घूमने वाले आठ ग्रहों का समूह है।
ग्रहों का क्रम
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
3. Continents (महाद्वीप)
Definition (English)
Large land masses on the Earth are called continents.
Example
Asia, Africa, Europe.
परिभाषा (Hindi)
पृथ्वी के बड़े भू-भागों को महाद्वीप कहते हैं।
Seven Continents
Asia
Africa
Europe
North America
South America
Australia
Antarctica
Important Facts
Asia → Largest Continent
Australia → Island Continent
Antarctica → White Continent
Africa → Dark Continent
4. Oceans (महासागर)
Definition (English)
Large bodies of salt water are called oceans.
परिभाषा (Hindi)
पृथ्वी पर खारे पानी के बड़े जल भागों को महासागर कहते हैं।
Five Oceans
Pacific Ocean
Atlantic Ocean
Indian Ocean
Southern Ocean
Arctic Ocean
Important Facts
Pacific → Largest & Deepest Ocean
Atlantic → Youngest Ocean
Indian → Named after a country
Arctic → Coldest Ocean
5. Axis (धुरी)
Definition (English)
The imaginary line passing through the centre of the Earth is called the Earth's axis.
Example
The Earth rotates on its axis.
परिभाषा (Hindi)
पृथ्वी के केंद्र से गुजरने वाली काल्पनिक रेखा को पृथ्वी की धुरी कहते हैं।
6. Poles (ध्रुव)
Definition (English)
The two end points of the Earth's axis are called the North Pole and the South Pole.
परिभाषा (Hindi)
पृथ्वी की धुरी के दोनों सिरों को उत्तर ध्रुव और दक्षिण ध्रुव कहते हैं।
7. Parallels / Latitudes (अक्षांश रेखाएँ)
Definition (English)
Imaginary circles drawn from east to west on the Earth's surface are called parallels or latitudes.
Example
Equator
परिभाषा (Hindi)
पूर्व से पश्चिम की ओर खींची गई काल्पनिक वृत्ताकार रेखाओं को अक्षांश कहते हैं।
Important Points
Run East to West.
Never meet each other.
Measure North-South position.
Total = 181 Latitudes.
8. Equator (भूमध्य रेखा)
Definition (English)
The Equator is the longest latitude at 0°. It divides the Earth into two equal halves.
परिभाषा (Hindi)
भूमध्य रेखा 0° अक्षांश है। यह पृथ्वी को उत्तरी और दक्षिणी गोलार्ध में बाँटती है।
9. Hemisphere (गोलार्ध)
Definition (English)
Each half of the Earth is called a hemisphere.
Types
Northern Hemisphere
Southern Hemisphere
परिभाषा (Hindi)
पृथ्वी के आधे भाग को गोलार्ध कहते हैं।
10. Tropic of Cancer (कर्क रेखा)
Definition (English)
The latitude 23½° North is called the Tropic of Cancer.
परिभाषा (Hindi)
23½° उत्तर अक्षांश को कर्क रेखा कहते हैं।
11. Tropic of Capricorn (मकर रेखा)
Definition (English)
The latitude 23½° South is called the Tropic of Capricorn.
परिभाषा (Hindi)
23½° दक्षिण अक्षांश को मकर रेखा कहते हैं।
12. Arctic Circle (आर्कटिक वृत्त)
Definition (English)
The latitude 66½° North is called the Arctic Circle.
परिभाषा (Hindi)
66½° उत्तर अक्षांश को आर्कटिक वृत्त कहते हैं।
13. Antarctic Circle (अंटार्कटिक वृत्त)
Definition (English)
The latitude 66½° South is called the Antarctic Circle.
परिभाषा (Hindi)
66½° दक्षिण अक्षांश को अंटार्कटिक वृत्त कहते हैं।
14. Meridians / Longitudes (देशांतर रेखाएँ)
Definition (English)
Imaginary lines joining the North Pole and the South Pole are called meridians or longitudes.
Example
Prime Meridian
परिभाषा (Hindi)
उत्तर ध्रुव और दक्षिण ध्रुव को जोड़ने वाली काल्पनिक रेखाओं को देशांतर कहते हैं।
Important Points
Run North to South.
Total = 360 Meridians.
Meet at the poles.
Measure East-West position.
15. Prime Meridian (प्रधान मध्याह्न रेखा)
Definition (English)
The 0° longitude passing through Greenwich is called the Prime Meridian.
परिभाषा (Hindi)
ग्रीनविच से गुजरने वाली 0° देशांतर रेखा को प्रधान मध्याह्न रेखा कहते हैं।
16. Grid (ग्रिड)
Definition (English)
The network formed by latitudes and longitudes is called a grid.
Example
A grid helps us locate places on the Earth.
परिभाषा (Hindi)
अक्षांश और देशांतर रेखाओं के जाल को ग्रिड कहते हैं।
17. GMT (Greenwich Mean Time)
Definition (English)
GMT is the worldwide standard time based on the Prime Meridian.
परिभाषा (Hindi)
ग्रीनविच मीन टाइम (GMT) विश्व का मानक समय है।
Important Point
India is 5 hours 30 minutes ahead of GMT (GMT +5:30).
18. AM and PM
AM (Ante Meridiem)
English: Time before noon (12:00 PM).
Hindi: दोपहर 12 बजे से पहले का समय।
PM (Post Meridiem)
English: Time after noon.
Hindi: दोपहर 12 बजे के बाद का समय।
Words to Learn
| English | Pronunciation | Hindi Meaning |
|---|---|---|
| Astronomer | एस्ट्रॉनमर | खगोल वैज्ञानिक |
| Navigator | नैविगेटर | समुद्री यात्री |
| Concentric Circles | कॉन्सेंट्रिक सर्कल्स | समान केंद्र वाले वृत्त |
| Circumference | सरकम्फरेंस | परिधि |
| Axis | एक्सिस | धुरी |
| Pole | पोल | ध्रुव |
| Latitude | लैटिट्यूड | अक्षांश |
| Longitude | लॉन्गिट्यूड | देशांतर |
| Hemisphere | हेमिस्फियर | गोलार्ध |
| Equator | इक्वेटर | भूमध्य रेखा |
| Grid | ग्रिड | जाल |
| GMT | जी एम टी | ग्रीनविच मानक समय |
Chapter 2 – The Earth – Our World
Exercise Answers (English)
A. Fill in the blanks
There are 360 meridians.
The Atlantic Ocean is the youngest ocean.
The meridians cut the parallels at right angles.
The 23½° N latitude is called the Tropic of Cancer.
The distance between any two meridians decreases as we move away from the Equator.
B. Write (T) for True and (F) for False
Indian Ocean is the only ocean named after a country. (T)
There are 181 meridians. (F)
The continent of Africa is made up entirely of islands. (F)
The 180°E and 180°W meridian are the same line. (T)
The meridian passing through Greenwich is numbered 90°. (F)
C. Answer these questions
1. How was it proved that the Earth is round?
It was proved when a Portuguese navigator sailed around the Earth by sea and returned to the same place after three years. This showed that the Earth is round.
2. Write a short note on parallels.
Parallels are imaginary circles drawn from east to west on the Earth's surface. They are also called lines of latitude. The Equator is the longest parallel. It divides the Earth into the Northern Hemisphere and the Southern Hemisphere. There are 181 parallels in total.
3. What are meridians? How many meridians are there?
Meridians are imaginary lines that join the North Pole and the South Pole. They are also called lines of longitude. There are 360 meridians in total.
4. What is the Prime Meridian?
The Prime Meridian is the 0° longitude that passes through Greenwich near London. It is used as the reference line for measuring longitude and calculating world time.
5. Which continent is also called the "Dark Continent"? Why?
Africa is called the "Dark Continent" because it remained unknown to much of the world for thousands of years.
HOTS
Why is India 5 hours 30 minutes ahead of Greenwich Mean Time (GMT)?
India follows Indian Standard Time (IST), which is based on 82½° East longitude. Therefore, India is 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT).
Picture Study
| Latitude | Passes Through |
|---|---|
| Arctic Circle | North America, Europe, Asia |
| Tropic of Cancer | North America, Africa, Asia |
| Equator | South America, Africa, Asia |
| Tropic of Capricorn | South America, Africa, Australia |
| Antarctic Circle | Antarctica |
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