Anything which have
mass and occupy space is
known as matter.
1) Matter is made up of particles.
2) The particlesof matter are very tiny.
3) The particlesof matterhave space between
4) The particlesof matter are continuously
5) The particlesof matter attract eachother.
Activity :-Take some water ina beaker and note its level. Dissolve
some salt or sugar 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 water get into the space between
the particles of water. This showsthat matter is made up of
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
showsthat a fewcrystals of potassium permanganate can colour
a large volume of water because there are millions of tiny
particles in each crystal.
Activity:- Take some waterin a beaker and note its level.
Dissolve some salt or sugar in it withthe help of a glass
rod. The salt dissolves in thewater but the level of water
does not change. This is because the particles of salt get
into the space between the particles of water.
Activity :- Take some water in a beakerand put a drop of blue or
red ink slowly along the sides of the beaker. Leaveit undisturbed
for a few hours. The ink spreads evenly throughout thewater due
to the movementof the particles of water and ink.
The intermixing of two or moredifferent types of matter on
their own is called diffusion.
Activity :- Take an iron nail, a piece of chalk and a rubber band.
Try breaking them by hammering, cutting or stretching. It is
moreeasier 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 rubberbandor chalk.
Matter is classified into three
The properties of Solid Stateare-
1) Solids have definiteshapes and fixedvolume.
2) The space between the particle is minimum.
3) The force of attraction between the particles is maximum.
4) The movement of the particles is minimum.
5) They are least compressible.
6) Their rate of diffusionis least.
1) Liquids have no definite shape but have fixed volume. Liquids
take the shape of the container.
2) The space betweenthe particles is intermediade.
3) The force of attraction betweenthe particles is intermediate.
4) The movementof the particles is intermediate.
5) They are less compressible.
6) Their rate of diffusion is more than solids.
1) Gases have no definite shape or fixed volume. Gases occupy
the wholespace of the container.
2) The space betweenthe particles is maximum.
3) The force of attraction betweenthe particles is minimum.
4) The movementof the particles is maximum.
5) They are most compressible.
6) Their rate of diffusion is more than solids and liquids.
Whena solid is heated it changes into liquid.When a
liquidis heated it changes into gas.
When agas is cooled it changes to liquid.Whena
liquidis cooled it changes into solid.
Eg:- If iceis heated it changes into water. If wateris
heated it changes into steam. Ifsteam is cooledit
changes intowater. If water is cooled it changes into ice.
Solid state Liquid state Gaseous state
The process of convertingsolid stateinto liquid
stateon heatingis known as melting(fusion).
LatentHeat Of Fusion-Latentheat of fusion is the
amount ofheat energyrequiredto change1 kgof
solidinto liquidat itsmelting point is known as
latentheat of fusion.
The Heatwhich gets used up in overcoming in changingthe state by
overcoming theforces of attractionbetweentheparticles. As this
heatenergy is absorbed by ice withoutshowing any rise in
temperature.it is considered thatit gets hidden into the contentsof
thebeaker and is known as LatentHeat.
The process of converting liquidintogases state
on heating is knownas boiling.
Latent Heat Of Vaporisation- The heat energy
requiredto change 1 kg ofliquidinto gasat
atmospheric pressure at its boilingpointis
knownas Latent heat of vaporisation.
A change directly from solid to gas without
changing into liquid state(or viceversa)is
Example- If solid camphor or ammonium
chloride is heated, it changes into vapour.
If the vapours are cooledit changes into
Whenpressure is applied on gas the particles come
closer and the gas changes into liquid.
We can liquefy gases by applying pressure andreducing
Compressed solid carbon dioxide is called dry ice. If the
pressure is reducedit changes directlyto gas without
coming into liquidstate. So solid carbon dioxide is
known adry ice.
Evaporation-The change ofa liquid into vapour at any temperature below its
boiling point is called evaporation.
Evaporation is a surfacephenomenon.Particles from the surface gain
enoughenergyto overcomethe forcesof attraction and changesto vapour
Factors Affecting Evaporation-The rate of evaporation dependsupon surface
area, temperature,humidityand wind speed.
Increase in the surfacearea increases the rate of evaporation.
Increase in temperature increases the rate ofevaporation.
Increase in humidity decreasesthe rate ofevaporation.
Increase in wind speedincreases the rate ofevaporation.
When a liquid evaporates, the particles of the liquid
absorb heat from the surroundings and evaporates. So
the surroundings become cold.
Eg :- People sprinklewater on the roof or open ground
because during evaporation water absorbs heat makes
the hot surface cool.
During summer we sweat more because during
evaporation the sweat absorbs heat from our body
makingthe body cool.
Wearing cotton clothes insummer keeps us cool
because cotton absorbs sweat and whenthe sweat
evaporates it absorbs heat from our body makingthe