1) Matter can exist in three states - solid, liquid, and gas - depending on temperature and pressure. 2) The particles that make up matter are in constant motion and attract each other, but can change arrangement depending on temperature. 3) Matter can change between solid, liquid, and gas states through processes like melting, boiling, evaporation, condensation, and sublimation caused by changes in temperature and pressure acting on the particles.

1. Change of state of matter
KAMLESH KUMAR
M.Sc. Microbiology

2. About matter…
Everything in this universe is made up of material which scientists have named “matter”.
The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of
water or a particle of sand- each thing is matter.
•MATTER IS MADE UP OF PARTICLES
•THESE PARTICLES ARE VERY SMALL- They are small even
beyond our imagination!
•THEY HAVE SPACE BETWEEN THEM
•THEY ATTRACT EACH OTHER

3. Can Matter Change its
State?
• Can matter really change its state?
• What happens to the particles of
matter during the change of its
state?
• How does this change of state take
place?

4. Can matter change its state?
https://www.youtube.com/watch?v=vNvElea-124
Solid, as ice
Liquid, as
water
Gas, as water
vapour

5. Liquid to gas - evaporation
1. Do you think that the puddle
will stay same?
2. Where does the water go?
3. Describe what the boys are
doing to measure the evaporation.

6. Water evaporates more quickly in some conditions
than in others

7. Gas to liquid- condensation

8. Condensation is
reverse of_________
Ans. evaporation

9. Darkling beetle live in Namib Desert in Africa, which is close
to the sea.
They stand on the top of sand dunes and
collect the water vapour that condenses
from the air.

10. Experiment…
Fig.: (a) Conversion of ice to water, (b) conversion of water to water vapour
Beaker Beaker
Burner Burner
Ice Water
Water vapour
(a) (b)

11. How this happens…
•The temperature at which a solid melts to become a liquid at the
atmospheric pressure is called its melting point.
•The temperature at which a liquid starts boiling at the atmospheric
pressure is known as its boiling point.
Solid State Liquid State Gaseous State
Heat Heat
Cool Cool

12. How this happens…
•A change of state directly from solid to gas without changing into
liquid state (or vice versa) is called sublimation.
Liquid
Solid Gas
Sublimation
Sublimation
Fig.: Interconversion of the three states of matter

13. Yes, matter can change its
state.
Thus, we can say that pressure and temperature determine the state of a substance,
whether it will be solid, liquid or gas.

14. Homework
Complete the activity given on page 29 & 30 in your Workbook.
• Watch this video for next lesson:
https://www.youtube.com/watch?v=e-2EoyDYamg