Class 9 · Social ScienceNCERT 2026 Revised Syllabus
Chapter 3: Atmosphere and Climate (0908CH03)
Understanding Society India and Beyond
Examines the composition and layered structure of the Earth's atmosphere, the elements of weather and climate, the mechanism of the Indian monsoon, and the challenge of climate change.
Chapter code: 0908ch03 · Book: Understanding Society India and Beyond · Class 9 Social Science
Find complete NCERT solutions for Class 9 Social Science, Understanding Society India and Beyond Chapter 3. Every question has a clear, step-by-step answer for chapter code 0908CH03.
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The Big Questions(4 questions)
1
What is the composition of the atmosphere?
Ans.
The atmosphere mainly contains nitrogen (78%) and oxygen (21%), with small amounts of carbon dioxide, argon, and other gases, plus water vapour and dust particles.
2
How do the different layers of the atmosphere affect the planet Earth?
Ans.
The troposphere gives us weather and breathable air; the stratosphere's ozone blocks harmful UV rays; the mesosphere burns up meteors; the thermosphere aids radio transmission and forms auroras; the exosphere merges into space.
3
What is the mechanism of monsoon?
Ans.
Monsoon occurs due to unequal heating of land and sea. In summer, low pressure over land draws moist winds from the ocean, causing rainfall; in winter, the reverse happens.
4
How can we reduce our carbon footprint?
Ans.
We can reduce our carbon footprint by saving energy, using public transport, adopting renewable energy, avoiding single-use plastics, and planting trees.
Introduction to the Atmosphere(1 questions)
1
Activity — THINK ABOUT IT: Can you imagine what would happen if there were no atmosphere?
Ans.
Without an atmosphere, there would be no air to breathe, extreme temperature swings between day and night, no protection from harmful UV rays, and no weather or rainfall.
Composition of the Atmosphere(1 questions)
1
Activity — LET'S RECALL: How is nitrogen useful for plants?
Ans.
Nitrogen is essential for making proteins and chlorophyll in plants. Certain soil bacteria convert atmospheric nitrogen into compounds that plant roots can absorb for growth.
Elements of Weather and Climate — Wind(2 questions)
1
Activity — THINK ABOUT IT: Other times when strong winds have caused problems for you.
Ans.
Sample answer: Strong winds have knocked over my umbrella in the rain, blown away loose papers, damaged trees and rooftops, and disrupted outdoor games and travel plans.
2
Activity — LET'S EXPLORE: Find other categories of wind based on speed and their common effects.
Ans.
Sample additions to Table 3.1: Gentle breeze (12–19 km/hr) — leaves and small twigs move constantly; Gale (62–88 km/hr) — breaks twigs, walking becomes difficult; Hurricane (above 118 km/hr) — causes widespread structural destruction.
Seasons in India(2 questions)
1
Activity — LET'S ANALYSE: Note the weather report from a local newspaper for two weeks.
Ans.
Sample observation: Over two weeks, temperature and humidity rose gradually, with a few days of light rain and mostly clear skies, showing a stable, slowly changing season.
2
Activity — THINK ABOUT IT: Which ragas of Hindustani Classical music are connected to each season?
Ans.
Sample answer: Raga Malhar is linked with the rainy season (Varsha), Raga Basant with spring (Vasanta), and Raga Bhairav is traditionally sung in the early morning of winter.
Monsoon(1 questions)
1
Activity — LET'S EXPLORE: Describe in your own words how monsoon affects the lives of people around you.
Ans.
Sample answer: Monsoon rains fill our wells and rivers and help farmers sow paddy, but heavy rainfall also floods roads and disrupts daily transport, school, and local markets.
Climate Change(1 questions)
1
Activity — LET'S EXPLORE: My Carbon Footprint — self-assessment and climate action pledge.
Ans.
This is a self-assessment activity — tick the option in each category (Transport, Electricity, Water, Waste/Plastics) that best matches your own habits, then add up the points as shown (Low = 1, Medium = 2, High = 3, Very high = 4) to get your personal score. Sample Climate Action Pledge (Step 3): I will switch off lights, fans, and other appliances whenever I leave a room. I will carry a reusable bottle and cloth bag instead of using single-use plastics.
Punjab Floods 2025 — Classroom Discussion(4 questions)
1
To what extent did natural factors cause these floods compared to human activities?
Ans.
Natural factors — heavy monsoon rain and western disturbances — triggered the floods, but human-made factors like weak embankments and river-bank encroachment worsened the damage.
2
Do you think better planning could have reduced the damage? How?
Ans.
Yes. Stronger embankments, timely desilting of rivers, restricting construction near riverbanks, and clear, early flood warnings could have reduced the extent of damage.
3
What are the guidelines for the management of floods according to the NDMA?
Ans.
NDMA guidelines include flood forecasting and warning systems, strengthening embankments, floodplain zoning, community preparedness drills, and coordinated relief and rescue operations.
4
What role can students/youth play in helping with disaster preparedness?
Ans.
Students can spread awareness, take part in mock drills, volunteer at relief camps, help elders and children evacuate safely, and share verified flood warnings within their community.
Questions and Activities (End of Chapter)(19 questions)
1
What is atmosphere? Explain its composition with the help of a pie diagram.
Ans.
The atmosphere is the blanket of air surrounding the Earth. It is mainly nitrogen (78%) and oxygen (21%), with small shares of argon, carbon dioxide, and other gases (draw the pie chart as shown in Fig. 3.2 of the chapter).
2
Draw a labelled diagram of the structure of atmosphere.
Ans.
Draw the five layers from the Earth's surface upward — Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere — labelling the tropopause, stratopause, and mesopause boundaries, as shown in Fig. 3.3.
3
Which are the four main seasons of India?
Ans.
The four main seasons recognised by the Indian Meteorological Department are winter, summer (pre-monsoon), monsoon (rainy/advancing monsoon), and post-monsoon (retreating monsoon).
4
Why do you not feel the pressure of the atmosphere?
Ans.
Air presses on our bodies equally from all sides, and the pressure inside our bodies balances this outside pressure, so we do not feel the weight of the atmosphere.
5
In which layer of the atmosphere do aeroplanes fly and why?
Ans.
Aeroplanes fly in the stratosphere because it is free of clouds, storms, and weather disturbances, which allows smoother and safer flight.
6(a)
Distinguish between the troposphere and the stratosphere.
Ans.
The troposphere is the lowest layer (up to about 12 km), where temperature falls with height and all weather occurs; the stratosphere lies above it (up to 50 km), is cloud-free, and contains the ozone layer.
6(b)
Distinguish between the south-west monsoon and the north-east monsoon.
Ans.
The south-west monsoon (June–September) blows moist winds from sea to land, bringing most of India's rainfall; the north-east monsoon (October–February) blows mainly dry winds from land to sea, causing rain chiefly on the south-eastern coast.
7
Do it yourself: Convert Table 3.3 data into temperature and rainfall graphs for the 10 stations.
Ans.
Practical task: For each station, plot monthly temperature as a line graph and monthly rainfall as bar graphs on the same axes, following the model of the Delhi graph in Fig. 3.14.
7.1
Re-arrange the 10 stations according to their distance from the equator.
Ans.
| Order | Station | Latitude |
|---|---|---|
| 1 | Thiruvananthapuram | 8°29′N |
| 2 | Bengaluru | 12°58′N |
| 3 | Chennai | 13°4′N |
| 4 | Mumbai | 19°N |
| 5 | Nagpur | 21°9′N |
| 6 | Kolkata | 22°34′N |
| 7 | Shillong | 24°34′N |
| 8 | Jodhpur | 26°18′N |
| 9 | Delhi | 29°N |
| 10 | Leh | 34°N |
7.2(a)
Which two stations have the most extreme climate?
Ans.
Leh and Jodhpur have the two largest annual temperature ranges in Table 3.3: Leh ranges from −8.5°C to 17.2°C, while Jodhpur ranges from 14.9°C to 33.9°C. Hence they show the most extreme temperature variation among the ten stations.
7.2(b)
Which two stations are influenced by retreating monsoons?
Ans.
Chennai and Thiruvananthapuram receive their heaviest rainfall in October–November from the retreating (north-east) monsoon, unlike most other stations that peak in June–September.
7.2(c)
Which are the two hottest stations in (i) February and (ii) June?
Ans.
February: Thiruvananthapuram and Chennai are the hottest. June: Jodhpur and Delhi are the hottest, both crossing 33°C due to their location in the dry interior of north-west India.
7.3(a)
Why does Shillong experience more rainfall than Kolkata?
Ans.
Shillong lies on windward hill slopes that force moist monsoon winds to rise, causing heavy orographic rainfall, while Kolkata, on the plains, receives comparatively less rain.
7.3(b)
Why does Delhi receive more rainfall than Jodhpur?
Ans.
Delhi lies closer to the monsoon currents moving up from the Bay of Bengal, while Jodhpur, deep in the arid Thar Desert, lies farther from these currents and receives scanty rainfall.
7.4(a)
Why does Thiruvananthapuram have an equable climate?
Ans.
Thiruvananthapuram has an equable climate because its coastal location moderates temperature. The nearby sea heats and cools more slowly than land, reducing the annual and seasonal temperature range.
7.4(b)
Why does Chennai receive more rainfall only after the monsoon's fury is over elsewhere?
Ans.
Chennai gets most of its rain from the retreating north-east monsoon (October–December), which picks up moisture crossing the Bay of Bengal after the south-west monsoon has withdrawn.
7.4(c)
Why does Leh have moderate precipitation almost throughout the year?
Ans.
Leh lies in the rain-shadow region beyond the Himalayas, so monsoon rain barely reaches it; its scant precipitation instead comes evenly from occasional snow and western disturbances.
7.5
Is there evidence that monsoons provide overall climatic unity to the whole country?
Ans.
Yes. Despite regional differences, most stations show a common rainfall peak in June–September, showing that the south-west monsoon governs rainfall patterns nationwide.
8
Collect pictures of houses and clothing from different regions of India and examine their relationship with climate/relief.
Ans.
Sample: Kerala houses have sloping roofs suited to heavy rainfall; Rajasthan homes have thick walls and small windows for a hot, dry climate; Ladakh homes have flat roofs and thick walls for cold, dry mountain conditions.