Class 6 Science | Chapter One: Our Earth | Chhattisgarh Board text book

Chapter 1: Our Earth - Summary and Questions

Summary of Chapter 1

This chapter introduces students to fundamental concepts about our planet Earth, including its structure, regions, place in the solar system, and what makes it unique for supporting life.

Structure of the Earth

The Earth has three main layers:

1. Crust: The outermost layer containing soil, water, minerals, and remains of dead organisms
2. Mantle: The middle layer composed of hot molten rocks and gases
3. Core: The innermost and hottest layer made primarily of iron and nickel

Regions of Earth

Earth's surface is divided into:

• Hydrosphere: All water bodies (oceans, lakes, rivers) and ice at poles (3/4 of Earth's surface)
• Lithosphere: The land portion with mountains, valleys, and plains (1/4 of Earth's surface)
• Atmosphere: The layer of air surrounding Earth containing nitrogen (78%), oxygen (21%), and other gases (1%)

Earth in the Solar System

• Earth is the third planet from the Sun in our solar system
• It has one natural satellite - the Moon
• Artificial satellites serve purposes like telecommunications and weather forecasting

Basic Needs for Life

Earth provides the essential requirements for life:

1. Food (energy source)
2. Water (70% of body weight)
3. Air (oxygen for breathing)
4. Soil and light (for plant growth)

Earth's Uniqueness

Earth is the only planet in our solar system that supports life because:

• It has liquid water in hydrosphere
• Atmosphere contains oxygen
• Atmosphere protects from extreme temperatures
• All basic life requirements are available

Questions from Chapter 1

1. Name the three layers of the earth.

The three layers of the earth are: (1) Crust, (2) Mantle, and (3) Core.

2. Name the various minerals found in the earth's crust.

Minerals found in the earth's crust include iron, aluminum, copper, coal, limestone, petroleum, and natural gases.

3. What is mantle?

The mantle is the middle layer of the Earth, consisting of a thick layer of hot molten rock along with many gases.

4. Name the metals found in the core of the earth.

The core mainly contains iron and nickel metals.

5. Fill in the blanks:

a. The earth has been divided into three regions Hydrosphere, Lithosphere, and Atmosphere.
b. At the Poles water is in solid form.
c. Three fourth part of the total area of the earth is Hydrosphere and one fourth part is Lithosphere.
d. Atmosphere has mainly Nitrogen, Oxygen and Carbon dioxide gases.
e. Carbon dioxide gas turns lime water milky.

6. Which is the planet nearest to the sun?

Mercury is the planet nearest to the sun.

7. Which is the planet farthest from the sun?

Neptune is the planet farthest from the sun.

8. With respect to the distance from the sun, what is the position of the earth?

Earth is the third planet from the sun.

9. Which is the planet nearest to the earth?

Venus is the planet nearest to the earth.

10. Name the natural satellite of the earth.

The Moon is the natural satellite of the earth.

11. Why do we eat food?

We eat food to obtain energy for our body to perform various activities.

12. Why is water necessary for living beings?

Water is necessary because it constitutes about 70% of body weight and is essential for all major activities and processes in living systems.

13. Where do aquatic organisms obtain O₂ from?

Aquatic organisms obtain oxygen dissolved in water.

14. How does soil help green plants?

Soil supports green plants to remain in position and provides nutrition to them.

Class 6 Science – Chapter 1: Our Earth

Questions and Answers

1. Choose the correct answer:

(i) Minerals are found in –

A. Crust ✅
Answer: Minerals are found in the Earth's crust, which is the outermost solid layer. It contains important natural resources like coal, petroleum, limestone, and metals such as iron and copper.

(ii) Which gas is required for respiration?

B. Oxygen ✅
Answer: Oxygen is the essential gas required for the process of respiration in humans and animals. It helps release energy from food in the body.

(iii) Which one is not a planet?

C. Moon ✅
Answer: The Moon is not a planet. It is a natural satellite of the Earth that revolves around it, whereas the other three are planets that revolve around the Sun.

(iv) Earth lies between –

C. Venus and Mars ✅
Answer: In the solar system, Earth is the third planet from the Sun. It is positioned between Venus (2nd) and Mars (4th).

2. Fill in the blanks:

• (i) The three main regions of the Earth are – Lithosphere, Hydrosphere, Atmosphere
• (ii) Water exists in solid form at the – Poles
• (iii) The hydrosphere covers 3/4th part and the lithosphere covers 1/4th part of the Earth's surface.
• (iv) The atmosphere contains gases like – Nitrogen, Oxygen, and Carbon dioxide
• (v) The gas that turns lime water milky is – Carbon dioxide

3. Write True or False:

• (i) The Sun is a star. – True
• (ii) The Moon is a natural satellite. – True
• (iii) Air is soluble in water. – True
• (iv) The Sun revolves around the Earth. – False
• (v) The core of the Earth contains iron and nickel. – True

4. Short Answer Questions:

Q1. What are the three main regions of Earth? Describe each.

Answer:
1. Lithosphere – The solid land surface including mountains, plains, and deserts.
2. Hydrosphere – The water bodies like oceans, rivers, and lakes, covering 75% of Earth.
3. Atmosphere – The layer of air containing nitrogen, oxygen, and other gases essential for life.

Q2. Why is Earth called a unique planet?

Answer: Earth is called a unique planet because it supports life. It has water, oxygen-rich atmosphere, moderate temperatures, and fertile soil.

Q3. What is the importance of the atmosphere?

Answer: The atmosphere provides oxygen, protects from harmful rays, regulates temperature, and supports the water cycle.

Q4. What are satellites? Name the two types.

Answer: Satellites are objects that revolve around planets. There are:
- Natural satellites (e.g., Moon)
- Artificial satellites (e.g., INSAT)

Q5. How do we know air is present in water?

Answer: When water is boiled, air bubbles rise from it, showing that air was dissolved in the water.

Q6. What is the composition of air?

Answer: Air is composed of 78% nitrogen, 21% oxygen, and 1% other gases like carbon dioxide and water vapor.

Q7. Why is oxygen important for living beings?

Answer: Oxygen is necessary for respiration. It helps living beings to release energy from food.

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