MATTER IN OUR SURROUNDING

Matter in Our Surroundings - Class 9 Science

What is Matter?

Everything around us that has mass and occupies space is called matter. For example, water, air, a book, and even your own body are all matter.

Characteristics of Matter

• Matter has mass: All objects, no matter how small, have weight because they have mass.
• Matter occupies space: For instance, when you pour water into a glass, it fills the glass.
• Matter is made of particles: Even the smallest piece of dust is made up of tiny particles.

States of Matter

Matter exists in three main states:

1. Solids
2. Liquids
3. Gases

1. Solids

• Have a fixed shape and volume.
• Particles are tightly packed and cannot move freely.
• Examples: Ice, wood, stone.

2. Liquids

• Do not have a fixed shape but have a fixed volume.
• Take the shape of the container they are in.
• Particles are less tightly packed than in solids and can move a little.
• Examples: Water, milk, oil.

3. Gases

• Do not have a fixed shape or volume.
• Particles are far apart and move freely.
• Examples: Air, steam, oxygen.

Changes in States of Matter

Matter can change from one state to another when we change temperature or pressure.

• Melting: Solid to liquid (e.g., ice to water).
• Freezing: Liquid to solid (e.g., water to ice).
• Boiling: Liquid to gas (e.g., water to steam).
• Condensation: Gas to liquid (e.g., steam to water).
• Sublimation: Solid to gas without becoming liquid (e.g., dry ice).

Key Terms

• Latent Heat: The heat required to change the state of matter without changing its temperature.
• Evaporation: The process where a liquid changes to gas below its boiling point.

Factors Affecting Evaporation

• Temperature: Higher temperature increases evaporation.
• Surface Area: Larger surface area increases evaporation.
• Wind Speed: Faster wind increases evaporation.
• Humidity: Less humidity increases evaporation.

Conclusion

The chapter explains the properties of matter, its states, and how it can change from one state to another. Understanding this helps us learn about the physical world around us and how it behaves.