Matter in Our Surroundings Class 9 Notes Science - Chapter 1

Matter in Our Surroundings Class 9 Notes: Everything around us is made of matter. The air we breathe, the water we drink, and the objects we use daily are all forms of matter. In Chapter 1 of Class 9 Science, titled Matter in Our Surroundings, you will learn about the different states of matter, their properties, and how they change under different conditions.

Our matter in our surroundings Class 9 notes thoroughly explain these CBSE concepts. These Class 9 Science Notes Chapter 1 cover CBSE Key Notes, Short Key Notes, CBSE Revision Notes, examples, images, and diagrams of Chapter 1 to help you understand the topic easily. Whether you are revising or preparing for exams, these Class 9 matter in our surroundings notes will make your learning smooth.

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CBSE Class 9 Science Notes Chapter - 1 Matter In Our Surroundings

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What is Matter?

Anything that occupies space and has mass is called Matter.

Physical Nature Of Matter

Matter is made up of particles.
The particles of matter are very small they are small beyond our imagination.

Characteristics Of Particles Of Matter

Particles of matter have space between them.
Particles of matter are continuously moving.
Particles of matter attract each other.

States Of Matter

There are three states of matter namely solid, liquid and gas.
The main difference between these states of matter are given below:

States Of Matter - Matter in Our Surroundings Class 9 Notes

Solid	Liquid	Gas
Definite shape	No definite shape	No definite shape
Distinct boundaries and fixed volume	Fixed volume	No fixed volume
Not compressible	Can be compressible	Highly compressible
Cannot flow	Can flow	Can flow
Very less inter-particle space	Inter-particle spaces are more than in solids	Large inter-particle space is available
Maximum density	Density is between that of the solids and gases	Minimum density
Negligible rate of diffusion	Density is between that of the solids and gases	Maximum rate of diffusion
Inter-particle attraction is maximum	Rate of diffusion depends on inter-particle attraction	Inter-particle attraction is minimum
	Inter-particle attraction is medium

Effect Of Temperature

The temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point.
The temperature at which a liquid starts boiling at the atmospheric pressure is known as its boiling point. Boiling is a bulk phenomenon.
The phase change phenomenon where the substance is transformed form liquid state to solid state is known as freezing point.
The phenomenon of changing of a liquid into its vapour state at any temperature below its boiling point is called evaporation. Evaporation is a surface phenomenon.

Factors affecting Evaporation

An increase in surface area increases evaporation.
An increase in temperature increases the rate of evaporation.
A decrease in humidity increases the rate of evaporation.
An increase in wind speed increases the rate of evaporation.
Evaporation causes cooling effect.

The change of the state of matter from the gas phase into liquid is known as condensation, it is reverse of evaporation.
A change of state directly from solid to gas without changing into liquid state (or vice versa) is called sublimation.
The phase change from the gaseous state to a solid state, without passing through the liquid state, is called deposition or re-sublimation.