This chapter is for class 9 based on CBSE curriculum in which physical nature of matter, its characteristics are discussed along with states of matter, their inconversion, scales of temperature and difference between boiling and evaporation and factors affecting evaporation with inforgraphics and key points.

1. MATTER IN OUR
SURROUNDINGS

2. Physical
Nature of
Matter
Characteristics
of Particles of
Matter
States of
Matter
Effect of
Temperature
and Pressure
Evaporation
Solids
Gases
Liquids
Melting Point
Latent Heat of
Vaporisation
Boiling Point
Latent Heat of
Fusion
TOPICS TO BE COVERED

3. MATTER
➔ Matter is anything which occupies space and has mass.
➔ Cannot gain 4 electrons to form C4- ion
CLASSIFICATION OF MATTER
➔ Early Indian philosophers classified in the form of five basic elements as air, earth, fire, sky and
water called Panch Tatva.
➔ On the basis of the physical state matter is classified as solids, liquids and gases.
➔ On the basis of chemical composition matter is classified as pure substances and mixtures. Pure
substances may be elements or compounds. Mixtures may be homogeneous mixtures or
heterogeneous mixtures.
➔ Cannot gain 4 electrons to form C4- ion
MATTER
PURE
SUBSTANCES
MIXTURES
HETEROGENEOUS
MIXTURES
HOMOGENEOUS
MIXTURES
COMPOUNDSELEMENTS

4. PHYSICAL NATURE OF MATTER
Matter is made up of particles. Matter can be broken into many pieces

5. CHARACTERISTICS OF PARTICLES OF MATTER
The particles of matter are very tiny.
The particles of matter have space
between them.
The particles of matter attract each other.
The particles of matter are continuously
moving.

6. Activity :- Take some water in a 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 salt get
into the space between the particles of water.
Particles of matter have space between them

7. Activity :- Take some water in a beaker and put a drop of blue or red ink
slowly along the sides of the beaker. Leave it undisturbed for a few hours.
The ink spreads evenly throughout the water due to the movement of the
particles of water and ink. The intermixing of two or more different types of
matter on their own is called diffusion.
Particles of matter are continuously moving

8. 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.
Particles of matter attract each other

9. 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.
Particles of matter are very tiny

10. STATES OF MATTER
PLASMA
GASES
LIQUIDS
SOLIDS
BOSON EINSTEIN
CONDENSATE (BEC)

11. STATES OF MATTER
➔ Definite shape and
volume
➔ Least Kinetic energy
➔ Strong Force of attraction
➔ Least Compressible
➔ Least Fluidity
➔ Minimum Brownian
motion
➔ Least Diffusion rate
SOLIDS
➔ Indefinite shape but
definite volume
➔ Less Kinetic energy
➔ Less Force of attraction
➔ Less Compressible
➔ Moderate Fluidity
➔ Moderate Brownian
motion
➔ Moderate Diffusion rate
LIQUIDS
➔ Indefinite shape and
volume
➔ High Kinetic energy
➔ Least Force of attraction
➔ Highly Compressible
➔ High Fluidity
➔ High Brownian motion
➔ High Diffusion rate
GASES

12. STATES OF MATTER
➔ Ionized gas
➔ Super energetic and
super excited particles
➔ Unstable gaseous
molecules
PLASMA
➔ Super cooled gas at
absolute Kelvin zero
temperature
BEC
QUARK GLUON
DEGENERATE MATTER
SUPER FLUID
OTHER STATES

13. TEMPERATURE AND TEMPERATURE SCALES
➔ Temperature is the degree of
hotness or coldness of body.
➔ There are different scales on which
temperature can be recorded.
Commonly used scales are Celsius,
Fahrenheit and Kelvin
➔ Relation between K & oC :
0 oC= 273 K
So, K = oC + 273 or oC = K -273
F = 9/5C + 32

14. MELTING AND BOILING
➔ When a solid is heated, the particles
begin to vibrate with greater speed and
begin to move more freely. Then at a
particular temperature the solid melts
and changes into liquid. The process of
melting is also known as fusion.
➔ The temperature at which a solid melts
is called its melting point. The melting
point of ice is 00C or 273 K.
➔ The amount of heat energy required to
change 1kg of a solid into liquid at
atmospheric pressure at its melting
point is called the latent heat of fusion.
➔ When a liquid is heated, its particles
begin to move even faster. Then at a
particular temperature the liquid begins
to boil and changes into gas (vapour).
Boiling is a bulk phenomenon.
➔ The temperature at which a liquid starts
boiling is called its boiling point. The
boiling point of water is 1000C or 373K
(273 + 100).
➔ The amount of heat energy required to
change 1kg of a liquid into gas at
atmospheric pressure at its boiling point
is called the latent heat of vaporisation.

15. INTERCONVERSION OF STATES OF MATTER
➔ The phenomenon due to which matter changes from one state to another and
then back to its original state on altering the conditions of temperature and
pressure is called interconversion of states of matter.
➔ The change of state directly from
solid to gas or from gas to solid is
called sublimation.
➔ The change of gaseous state to
liquid state on cooling is called
condensation.
➔ The change of liquid state of a
substance to gaseous state at
boiling point is called
vapourisation.
➔ The change of solid state of a
substance to liquid state at melting

16. EFFECT OF TEMPERATURE
On increasing temperature, the kinetic energy of the particles of the matter
increases and they begin to vibrate with a higher energy. Therefore, the
interparticle force of attraction between the particles reduces and particles
get detached from their position and begin to move freely.
➔ As a result, the state of matter begins to change.
➔ Solids undergo a phase change to form liquids.
➔ Similarly, liquids also undergo a phase change to form gases.

17. EFFECT OF PRESSURE
By applying pressure, the interparticle spaces between particles of matter
decreases. Thus, by applying pressure and reducing temperature we can
convert a solid to liquid and a liquid to gas.

18. EVAPORATION
➔ The phenomenon of change of
a liquid into vapors at any
given temperature below its
boiling point is called
Evaporation.
➔ Evaporation is different than
boiling.
➔ The particles of liquids have
more kinetic energy.
Therefore, they are able to
overcome the forces of
attraction and convert into
vapor without any external
forces.

19. FACTORS AFFECTING EVAPORATION
➔ Increase in surface area facilitates more space which helps in faster
evaporation.
➔ Increase in temperature increase kinetic energy which overcome interparticle
force of attraction between particles. Hence, increase in evaporation.
➔ High water content in atmosphere (Humidity) decreases rate of evaporation
as less space is present to accommodate water particles in the atmosphere.
➔ High wind speed blow away water vapours allowing faster evaporation rate.
SURFACE AREA WIND SPEEDHUMIDITYTEMPERATURE

20. EVAPORATION CAUSES COOLING
➔ Evaporation is a surface
phenomenon. The particles at
the surface having high K.E.
break up their force of
attraction & form vapours.
Since the energy is lost, that
means temperature gets
lowered and low temperature
means cooling effect so,
evaporation results in cooling
effect.