In this chapter we have discussed matter present in our surroundings, it's particles and their characteristics. and also daily life science phenomena.

1. MATTER IN OUR
SURROUNDINGS
BHARAT GURUKUL

2. INTRODUCTION
•MATTER: Matter is the substance which have mass and
occupies space and matter is made up of tiny particle.
•Matter in the form of five basic elements - the “Panch
Tatva”- air, earth, fire, sky and water.
Examples: notebook, pen, pencil, table, tree, chair etc.

3. PHYSICAL NATURE OF MATTER
•Matter is made up of particles.
•How small are these particles of matter?
•The particles of matter are very small they are small
beyond our imagination.

4. CHARACTERISTICS OF PARTICLES OF
MATTER
•Particles of matter have space between them.
•Particles of matter are continuously moving.
•Particles of matter attract each other.

5. PARTICLES OF MATTER HAVE SPACE
BETWEEN THEM
• Particles of one type of matter get into the spaces between particles of the
other. This shows that there is enough space between particles of matter.
• Example- Salt solution(salt fully dissolved in water and disappear).

6. PARTICLES OF MATTER ARE
CONTINUOUSLY MOVING
• They possess kinetic energy, as the temperature rises particles move faster.
• Increase in temperature the kinetic energy of the particles also increases.
• Diffusion- The particles of matter intermix on their own with each other, they do
so by getting into the spaces between the particles. This intermixing of particles
of two different types of matter on their own is called diffusion.

7. PARTICLES OF MATTER ATTRACT EACH
OTHER
• Particles of matter have force acting between them.
• This force keeps the particles together.
• The strength of this force of attraction varies from one kind of matter
to another.

8. STATES OF MATTER

9. SOLID STATE
•Have a definite shape
•Distinct boundaries
•Fixed volumes
•Have negligible compressibility.
•Solids may break under force but it is difficult to change
their shape, so they are rigid.

10. LIQUID STATE
• Have no fixed shape
• Have a fixed volume.
• No definite boundaries
• Liquids flow and change shape, so they are not rigid but can be called
fluid.
• The rate of diffusion of liquids is higher than that of solids. This is due
to the fact that in the liquid state, particles move freely and have
greater space between each other as compared to particles in the solid
state.

11. GASEOUS STATE
• No definite shape
• No definite boundaries
• Fluidity
• Highly compressible
• No definite volume
• Due to high speed of particles and large space between them, gases show the
property of diffusing very fast into other gases.
• Liquefied petroleum gas (LPG)
• Compressed natural gas (CNG)

12. SPACE AMONG DIFFERENT STATES OF
PARTICLES

13. CAN MATTER CHANGE ITS STATE?
- Water can exist in three states of matter–
• Solid, as ice,
• Liquid, as the familiar water, and
• Gas, as water vapor.

14. LET’S THINK
•What happens inside the matter during this change of state?
•What happens to the particles of matter during the change of
states?
•How does this change of state take place?

15. EFFECT OF CHANGE OF
TEMPERATURE
• Melting point- The temperature at which a solid melts to become a liquid at the
atmospheric pressure is called its melting point.
The melting point of ice is 273.16 K.(SI unit of temperature is kelvin, 0degree C
=273.16 K).
• Change of solid state into liquid state is also known as fusion.
• Latent heat of fusion- The amount of heat energy that is required to change 1 kg
of a solid into liquid at atmospheric pressure at its melting point is known as the
latent heat of fusion.

16. Melting of ice Boiling of water

17. •Boiling point- The temperature at which a liquid starts boiling
at the atmospheric pressure is known as its boiling point.
•Latent heat of vaporization- the amount of heat energy that is
required to change 1 kg liquid into its gaseous state at
atmospheric pressure at its boiling point is known as the latent
heat of vaporization.
•So, the state of matter can be changed into another state by
changing the temperature.

18. •There are some susbtances that change directly from solid
state to gaseous state and vice versa without changing into the
liquid state.
•A change of state directly from solid to gas without changing
into liquid state or vice versa is called sublimation.
•Examples- Camphor, Naphthalene balls, Ammonium chloride
etc.

19. LET’S THINK
• What will happen if we start putting pressure and compress a gas
enclosed in a cylinder?
• Will the particles come closer?
• Do you think that increasing or decreasing the pressure can change the
state of matter?

20. EFFECT OF CHANGE OF PRESSURE
• By applying pressure the space between particles of matter decreases
So, thus by applying pressure and reducing temperature we will be
able to convert a gas into liquid and a liquid into solid.

21. INTERCONVERSION OF THREE STATES
OF MATTER

22. EVAPORATION
• The phenomenon of change of a liquid into vapors at any temperature
below its boiling point is called evaporation.
• Factors affecting evaporation.
1. Exposed surface area: The rate of evaporation increases with an increase
in surface area.
2. Temperature: The rate of evaporation increases with an increase in
temperature.
3. Humidity: The rate of evaporation decreases with an increase in humidity.
4. Wind: The rate of evaporation increases with an increase in wind speed.

23. HOW DOES EVAPORATION CAUSE
COOLING?
• In an open vessel, the liquid keeps on evaporating. The particles of
liquid absorb energy from the surrounding to regain the energy lost
during evaporation. This absorption of energy from the surroundings
make the surroundings cold.
• Why should we wear cotton clothes in summer?
• Why do we see water droplets on the outer surface of a glass
containing ice-cold water?

24. THANK YOU
BHARAT GURUKUL