NCERT Class 9 Science Exploration: Chapter 13 — 13. Earth as a System: Energy, Matter, and Life
This chapter, "Earth as a System: Energy, Matter, and Life," from NCERT Class 9 Science Exploration, delves into the interconnectedness of Earth's spheres. It explains how the Sun is the primary energy source, driving processes like wind and the water cycle, while Earth's interior and chemical reactions also contribute. The chapter introduces the five spheres: Geosphere (rocks, soil), Hydrosphere (water bodies), Cryosphere (ice, snow), Atmosphere (air), and Biosphere (living organisms). It emphasizes that changes in one sphere, such as reduced snowfall affecting lake levels or warmer seas influencing monsoons, can have cascading effects on others. Understanding these interactions is crucial for comprehending the delicate balance of Earth's systems and how human activities impact them, preparing students for a deeper exploration of science.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 9 |
| Subject | Science |
| Book | Exploration |
| Chapter | Chapter 13 — 13. Earth as a System: Energy, Matter, and Life |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 572 |
Learning outcomes
- Identify and describe the five spheres of the Earth system: Geosphere, Hydrosphere, Cryosphere, Atmosphere, and Biosphere.
- Explain how energy and matter move and interact across these spheres.
- Analyze the interconnectedness of Earth's spheres and how a disturbance in one can affect others.
- Understand the role of solar radiation as the primary energy source for Earth's processes.
- Recognize the impact of natural processes and human activities on the Earth system.
Vocabulary
| Word | Meaning |
|---|---|
| Geosphere | The solid part of the Earth, including rocks, soil, and landforms. |
| Hydrosphere | All the water on Earth's surface, such as oceans, rivers, and lakes. |
| Cryosphere | The frozen water part of the Earth system, including ice and snow. |
| Atmosphere | The layer of gases surrounding the Earth. |
| Biosphere | All living organisms and their habitats on Earth. |
| Solar radiation | Energy emitted by the Sun in the form of electromagnetic waves. |
| Nutrient cycling | The movement and exchange of organic and inorganic matter back into the production of living matter. |
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Practice questions
- Name the five spheres of the Earth system. Answer: Geosphere, Hydrosphere, Cryosphere, Atmosphere, and Biosphere.
- What is the main source of energy for life on Earth? Answer: The Sun is the main source of energy.
- How does a disturbance in the cryosphere potentially affect the hydrosphere? Answer: Less snowfall (cryosphere) can lead to less water in lakes and rivers (hydrosphere) in the summer.
- What is the role of the atmosphere in the Earth system? Answer: The atmosphere is the air surrounding the Earth that we breathe and it plays a role in weather and climate.
Frequently asked questions
What are the main components of the Earth system discussed in the chapter?
The chapter discusses five main spheres: Geosphere, Hydrosphere, Cryosphere, Atmosphere, and Biosphere.
Where does most of the energy for Earth's processes come from?
The Sun is the primary source of energy for most of Earth's processes.
Can a change in one sphere of the Earth affect another?
Yes, the chapter explains that a disturbance in one sphere can lead to changes in others, illustrating their interconnectedness.
What is the hydrosphere?
The hydrosphere includes all liquid water on Earth's surface, such as oceans, rivers, and lakes, as well as groundwater.
How does the cryosphere relate to the hydrosphere?
The cryosphere is the frozen water part (ice and snow), which can melt and become part of the hydrosphere (liquid water).
What is the biosphere?
The biosphere encompasses all living organisms and their habitats on Earth.
Related resources
Important topics
Topics covered
NCERT Class 9 Science — Exploration — Chapter 13 — 13. Earth as a System: Energy, Matter, and Life. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.