🌍 Class 5 – Chapter 9: Our Environment
Hydrosphere • Atmosphere • Lithosphere • Biosphere
📘 Detailed Notes
The Environment is everything around us – air, water, land, plants, animals, and people. It is divided into four main spheres: Hydrosphere, Atmosphere, Lithosphere, and Biosphere. Together, they make life possible on Earth. 🌍
🌊 1. Hydrosphere
- Made of all water on Earth – oceans, seas, rivers, lakes, ponds, glaciers, and underground water.
- 🌐 Covers 71% of Earth’s surface (mostly oceans).
- 💧 Fresh water is found in rivers, lakes, ponds, and groundwater.
- Importance:
- Provides drinking water.
- Home to aquatic life like fish 🐟 and dolphins 🐬.
- Used in transport, irrigation, and power generation.
🌬️ 2. Atmosphere
- The blanket of air
- Made of gases:
- 🌱 Nitrogen (78%) – helps plants grow.
- 🌬️ Oxygen (21%) – needed for breathing.
- 💨 Other gases (1%) – carbon dioxide, argon, etc.
- Functions:
- Provides air to breathe.
- Protects from harmful Sun rays (ozone layer).
- Controls Earth’s temperature.
- Helps in weather changes 🌧️☁️.
🏔️ 3. Lithosphere
- The solid outer layer
- It is the base of all human activities – farming, building, mining ⛏️.
- Provides:
- Soil for crops 🌾.
- Minerals, coal, oil ⛽.
- Forests for wood, medicine, oxygen 🌳.
🌱 4. Biosphere
- The sphere of life
- Depends on:
- 💧 Water (Hydrosphere).
- 🌬️ Air (Atmosphere).
- 🏔️ Land (Lithosphere).
- Life is connected through the Food Chain 🍃➡️🐇➡️🐅.
- If disturbed by pollution/deforestation, life is in danger ⚠️.
✨ Summary
- Hydrosphere: All water on Earth.
- Atmosphere: Air surrounding Earth.
- Lithosphere: Solid land part.
- Biosphere: Living world of plants, animals, humans.
📖 Textbook Questions & Answers
A. Choose the correct answer.
1. What per cent of earth is covered by land?
Ans: (b) 29 per cent ✅
2. Which of these are the main sources of fresh water?
Ans: (d) All of these – Rivers, Lakes, and Ponds ✅
3. Which of these help in the formation of clouds?
Ans: (b) Water vapour ✅
4. Which is the most important gas for our survival?
Ans: (a) Oxygen ✅
5. What is the layer below the crust known as?
Ans: (a) Mantle ✅
B. Match the columns.
| Column A | Column B |
|---|---|
| 1. Nitrogen | 78 per cent |
| 2. Argon | Other gas present in atmosphere |
| 3. Oxygen | 21 per cent |
| 4. Lithosphere | Also called crust |
| 5. Biosphere | Living organisms exist |
C. Fill in the blanks.
1. Our __________ is the natural world in which people, animals and plants live.
Ans: Environment ✅
2. Our environment consists of __________ spheres.
Ans: Four ✅
3. The __________ includes all water bodies.
Ans: Hydrosphere ✅
4. __________ is the gaseous layer surrounding the earth.
Ans: Atmosphere ✅
5. __________ is needed by the plants for making food.
Ans: Carbon dioxide ✅
D. Unscramble the letters to form the correct words.
1. Life found in sea water: (AINMER FILE)
Ans: Marine Life ✅
2. The gas needed by plants for making food: (NOBA CR IDIXODE)
Ans: Carbon Dioxide ✅
3. The surface of the earth made up of rock and soil: (ITOLSH PEREH)
Ans: Lithosphere ✅
4. The innermost layer of the earth: (ORCE)
Ans: Core ✅
5. The sphere in which life is found: (IOPBS HERE)
Ans: Biosphere ✅
E. Answer the following questions.
1. What is the difference between crust and core?
Ans: The crust is the thin outermost solid layer of the Earth, while the core is the innermost and hottest layer. 🌍
2. List the importance of the hydrosphere.
Ans: It provides drinking water, supports aquatic life, helps in irrigation, transport, and electricity generation. 💧
3. Explain the water cycle.
Ans: Water evaporates, forms clouds through condensation, and falls back as rain, completing the cycle. 🌧️☀️
4. Name the gases found in the atmosphere.
Ans: Nitrogen (78%), Oxygen (21%), Carbon dioxide, Argon, and other gases. 🌬️
5. Why is the biosphere so important?
Ans: Because it is the sphere of life – it provides food, water, air, and shelter needed by all living beings. 🌱
