Class 9 cbse chapter 1 notes

●​ CHAPTER 1 : Matter in Our Surrounding




Matter : -

Matter is anything that occupies space and has mass.

Everything around us—air, water, soil, and living beings—is matter.

Matter can exist in different forms based on physical and chemical properties.




Physical Nature of Matter : -

1. Particles of matter are very small – they are so tiny that we cannot see them with naked eyes.


2. Particles of matter have space between them – this is called inter-particle space.


3. Particles of matter are continuously moving – they possess kinetic energy.


4. Particles of matter attract each other – the force of attraction varies from one type of matter to
another.




States of Matter : -

There are 5 states of matter known:

1. Solid


2. Liquid

, 3. Gas


4. Plasma (not in syllabus)


5. Bose-Einstein Condensate (not in syllabus)


1.Solid

1.Definite shape and volume.

2. Particles are tightly packed.

3. Incompressible.

4. Low kinetic energy.

5. Example: Ice, wood, iron.


2. Liquid

1.No fixed shape but has fixed volume.

2.Particles are less tightly packed.

3.Can flow and take the shape of container.

4.Slightly compressible.

5.Example: Water, oil, milk.


3. Gas

1.No fixed shape or volume.

2.Particles are far apart and move freely.

3.Highly compressible.