Class: 6th

Subject: Physics

Chapter Title: Matter

Chapter No: 1

1a) Matter :-Matter is anything which occupies space and has mass, it can be

perceived by our senses.

For better understanding: https://youtu.be/QQsybALJoew

b) Classification of matter:-• Early Indian philosophers classified matter in the form of five basic

elements as air, earth, fire, sky and water called Panch Tatva.

• Maharshi Kannad, an Indian philosopher suggested that every matter

is made up of small particles called anu(atom) and that every anu

(atom) is composed of very small particles called parmanu

(molecule).

b) Classification of matter(contd) :-

• A molecule consisting of one atom is called monoatomic

molecule eg. Neon,argon etc

• A molecule having two atom is called diatomic molecule. eg.

Hydrogen,oxygen

• On the basis of the physical state, matter is classified as solids,

liquids and gases.

• For better understanding: https://youtu.be/68QDZAl29oE

2) Characteristics of particle of matter :-a) The particles of matter are very tiny.

b) The particles of matter have space between them.

c) The particles of matter are continuously moving.

d) The particles of matter attract each other.

a) The particles of matter are very tiny :-

Activity :- Dissolve 2 – 3 crystals of potassium permanganate in

100ml of water in a beaker. Take 10ml of this solution and dissolve in

100ml of water. Take 10ml of this solution and dissolve in 100ml of

water. Repeat this process 5 – 6 times. This shows that a few crystals of

potassium permanganate can colour a large volume of water because

there are millions of tiny particles in each crystal.

b) The particles of matter have space between them :-

The spacing between molecules of matter is called inter-molecular

space.

Activity :- Take 100 ml of water in a measuring cylinder. Dissolve

200gm salt in it with the help of a glass rod. The salt dissolves in the

water but the level of water does not change. This is because the

particles of salt get into the space between the particles of water.

c) Particles of matter are continuously moving :-

Activity :- Take a beaker fill it partly with water. Add some Iycopodium

powder in the beaker containing water. Stir it. Take out few drops of

suspension on a glass plate. Place the plate on table and illuminate it

with lamp. Observe the glass plate through a microscope. It is found

that fine particles of powder move in random pattern and their path is

as shown in fig.

d) Particles of matter attract each other :-

Activity :- Take an iron nail, a piece of chalk and a rubber band. Try

breaking them by hammering, cutting or stretching. It is more easier

to break the chalk, less easier to break the rubber band and difficult

to break the iron nail. This is because the particles in the iron nail are

held together with greater force than in the rubber band or chalk.

3) States of matter :-

Matter exists in three different states.

They are :- a) Solid b) Liquid c) Gas

For eg: Steel is solid, Oil is liquid and air is mixture of gases

For better understanding:https://youtu.be/3IW8E1YR0kE

Water can exists in all three states ice(solid state), water(liquid

state) and steam(gaseous state)

The force of attraction between the molecules of the same

substance is called the force of cohesion, while the force of

attraction between the molecules of different substance is called

force of adhesion.

Properties of States of matter:

i) Inter-molecular space

ii) Force of attraction between the molecules

iii) Movement of molecules

For better understanding: https://youtu.be/GKl7CxE6-x8

a) Properties of solids :-

i) Solids have definite shapes and fixed volume.

ii) The space between the particle is minimum.

iii) The force of attraction between the particles is maximum.

iv) The movement of the particles is minimum.

v) They are least compressible.

vi) Their rate of diffusion is least.

b) Properties of liquids :-

i) Liquids have no definite shape but have fixed volume. Liquids take

the shape of the container.

ii) The space between the particles is intermediade.

iii) The force of attraction between the particles is intermediate.

iv) The movement of the particles is intermediate.

v) They are less compressible.

vi) Their rate of diffusion is more than solids.

c) Properties of gases :-

i) Gases have no definite shape or fixed volume. Gases occupy the

whole space of the container.

ii) The space between the particles is maximum.

iii) The force of attraction between the particles is minimum.

iv) The movement of the particles is maximum.

v) They are most compressible.

vi) Their rate of diffusion is more than solids and liquids.

The change in state of matter of a substance from solid to

liquid or from liquid to gas is brought by imparting heat

energy to it at a constant temperature.

i) Change from solid state to liquid state

ii) Change from liquid state to gaseous state

For better understanding: https://youtu.be/EwzkYTfHFbo

4) Change in state of matter :-

i) Change from solid state to liquid state

• The process of changing of a substance from a solid state into

its liquid state of absorption of heat at particular temperature,

called the melting point, is called melting or fusion.

• The heat energy absorbed by the substance increases the

amplitude of vibration of molecules of the solid and the stage is

reached at the melting point when the molecules acquire

sufficient energy to overcome the force of attraction between

them and they become free to move. The solid thus changes in

liquid.

• The process of change of a substance from liquid state to

gaseous state at a particular temperature, is called the boiling

point,is called boiling or vaporisation.

• The heat energy absorbed by the substance in liquid state

increases the enery of its molecules due to which they begin to

move rapidly. Thus a liquid changes into gas.

• Melting point of ice is 0oC.

• Boiling point of water is 100oC.

ii) Change from liquid state to gaseous state

Illustration:When a solid is heated it changes into liquid. When a liquid is heated

it changes into gas.

When a gas is cooled it changes to liquid. When a liquid is cooled it

changes into solid.

Eg:- If ice is heated it changes into water. If water is heated it changes

into steam. If steam is cooled it changes into water. If water is cooled it

changes into ice.

Heat Heat

Cool Cool Solid state Liquid state Gaseous state

• https://youtu.be/68QDZAl29oE

• https://youtu.be/GKl7CxE6-x8

• https://youtu.be/QQsybALJoew

• https://youtu.be/3IW8E1YR0kE

• https://youtu.be/EwzkYTfHFbo

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