CBSE Class 6 General Knowledge

Unit 4: Science & Technology

Lesson: Matter and Its States

📘 Study Module: Matter and Its States

1. Introduction

Everything around us occupies space and has mass. Such things are called matter. Matter exists in different forms called states of matter, which depend on temperature and pressure.

2. Meaning of Matter

Matter is anything that has mass and occupies space. Air, water, soil, books, and even our body are examples of matter.

3. States of Matter

Matter exists mainly in three states:

• Solid
• Liquid
• Gas

Each state has different properties.

4. Solids

Solids have a fixed shape and fixed volume. Their particles are closely packed. Examples include stone, wood, and ice.

5. Liquids

Liquids have a fixed volume but no fixed shape. They take the shape of the container. Examples include water, milk, and oil.

6. Gases

Gases have neither fixed shape nor fixed volume. They spread in all directions. Examples include air, oxygen, and carbon dioxide.

7. Change of State

Matter can change from one state to another due to heating or cooling. For example, ice changes to water on heating and water changes to ice on cooling.

8. Importance of Matter

Understanding matter helps us understand natural processes and daily life activities such as cooking, freezing, and evaporation.

📝 Questions and Answers

A. Short Answer Questions

(One sentence each)

1. What is matter?
   Answer: Matter is anything that has mass and occupies space.
2. Name the three states of matter.
   Answer: Solid, liquid, and gas.
3. Which state of matter has a fixed shape?
   Answer: Solid has a fixed shape.
4. Which state of matter has no fixed shape but fixed volume?
   Answer: Liquid has fixed volume but no fixed shape.
5. Which state of matter spreads in all directions?
   Answer: Gas spreads in all directions.
6. Give one example of a solid.
   Answer: Stone is an example of a solid.
7. Give one example of a liquid.
   Answer: Water is an example of a liquid.
8. Give one example of a gas.
   Answer: Oxygen is an example of a gas.
9. What happens to ice when heated?
   Answer: Ice melts and changes into water.
10. What is change of state?
    Answer: Change of state is the conversion of matter from one form to another.

B. Long Answer Questions

(3–5 sentences each)

11. Explain the meaning of matter with examples.
    Answer: Matter is anything that occupies space and has mass. It includes solids, liquids, and gases. Objects like books, water, and air are all matter. Matter is found everywhere around us.
12. Describe the properties of solids.
    Answer: Solids have a fixed shape and fixed volume. Their particles are tightly packed. They are generally hard and cannot flow. Examples include wood and iron.
13. Describe the properties of liquids.
    Answer: Liquids have a fixed volume but no fixed shape. They can flow easily. Liquids take the shape of the container they are kept in. Water and milk are common examples.
14. Describe the properties of gases.
    Answer: Gases have neither fixed shape nor fixed volume. Their particles are far apart. They spread quickly in all directions. Air is a common gas.
15. What is change of state? Explain with examples.
    Answer: Change of state occurs when matter changes from one form to another. Heating and cooling cause this change. Ice changes to water on heating. Water changes to ice on cooling.
16. Explain melting.
    Answer: Melting is the process by which a solid changes into a liquid on heating. Ice melts to form water. Heat energy helps particles move freely. Melting occurs at a fixed temperature.
17. Explain freezing.
    Answer: Freezing is the process by which a liquid changes into a solid on cooling. Water freezes to form ice. Particles lose energy and come closer. Freezing happens at a fixed temperature.
18. How does heating affect matter?
    Answer: Heating increases the energy of particles. Particles move faster and spread apart. This can change the state of matter. Solids may become liquids and liquids may become gases.
19. How does cooling affect matter?
    Answer: Cooling decreases the energy of particles. Particles move slowly and come closer. This can change liquids into solids. Cooling causes freezing.
20. Why is the study of matter important?
    Answer: The study of matter helps us understand the physical world. It explains daily activities like boiling and freezing. It helps in scientific learning. Matter is the basis of all substances.

🧠 Multiple Choice Questions (MCQs)

(With Answers and Detailed Explanations)

1. Matter is anything that has ______.
   a) colour
   b) shape
   c) mass and space
   d) size only
   Answer: c) mass and space
   Explanation: Matter has mass and occupies space.
2. Which of the following is a solid?
   a) Air
   b) Water
   c) Stone
   d) Oxygen
   Answer: c) Stone
   Explanation: Stone has a fixed shape.
3. Which state of matter has a fixed volume but no fixed shape?
   a) Solid
   b) Liquid
   c) Gas
   d) Plasma
   Answer: b) Liquid
   Explanation: Liquids take the shape of the container.
4. Which of the following is a gas?
   a) Milk
   b) Oil
   c) Oxygen
   d) Ice
   Answer: c) Oxygen
   Explanation: Oxygen is a gas.
5. Solids have ______ shape.
   a) no
   b) changing
   c) fixed
   d) round
   Answer: c) fixed
   Explanation: Solids maintain their shape.
6. Gases spread in ______.
   a) one direction
   b) two directions
   c) all directions
   d) no direction
   Answer: c) all directions
   Explanation: Gas particles move freely.
7. Ice changes into water by ______.
   a) freezing
   b) melting
   c) cooling
   d) condensation
   Answer: b) melting
   Explanation: Melting changes solid to liquid.
8. Which process changes liquid into solid?
   a) Melting
   b) Evaporation
   c) Freezing
   d) Boiling
   Answer: c) Freezing
   Explanation: Freezing converts liquid to solid.
9. Which state of matter has particles far apart?
   a) Solid
   b) Liquid
   c) Gas
   d) Ice
   Answer: c) Gas
   Explanation: Gas particles are far apart.
10. What causes change of state?
    a) Colour
    b) Size
    c) Heating and cooling
    d) Shape
    Answer: c) Heating and cooling
    Explanation: Temperature change causes state change.
11. Water is a ______ at room temperature.
    a) solid
    b) gas
    c) liquid
    d) metal
    Answer: c) liquid
    Explanation: Water flows and takes container shape.
12. Which has no fixed volume?
    a) Solid
    b) Liquid
    c) Gas
    d) Ice
    Answer: c) Gas
    Explanation: Gases expand freely.
13. Heating a liquid can change it into a ______.
    a) solid
    b) gas
    c) metal
    d) ice
    Answer: b) gas
    Explanation: Heating causes evaporation or boiling.
14. Freezing occurs due to ______.
    a) heating
    b) pressure
    c) cooling
    d) melting
    Answer: c) cooling
    Explanation: Cooling reduces particle energy.
15. Which is not a state of matter?
    a) Solid
    b) Liquid
    c) Gas
    d) Energy
    Answer: d) Energy
    Explanation: Energy is not matter.
16. Milk takes the shape of the container because it is a ______.
    a) solid
    b) liquid
    c) gas
    d) metal
    Answer: b) liquid
    Explanation: Liquids take container shape.
17. Which state of matter can be compressed easily?
    a) Solid
    b) Liquid
    c) Gas
    d) Ice
    Answer: c) Gas
    Explanation: Gases are easily compressible.
18. Ice, water, and steam are forms of ______.
    a) air
    b) matter
    c) metal
    d) soil
    Answer: b) matter
    Explanation: All are states of matter.
19. What happens to particles when heated?
    a) They stop
    b) They move faster
    c) They disappear
    d) They freeze
    Answer: b) They move faster
    Explanation: Heat increases particle movement.
20. Study of matter helps us understand ______.
    a) only science
    b) only food
    c) daily life activities
    d) only machines
    Answer: c) daily life activities
    Explanation: Matter explains everyday changes.

✅ End of Lesson

Prepared strictly in accordance with the NCERT syllabus and CBSE Class 6 examination standards.