This ppt prepared by Student-Teacher from Thiagarajar College of Preceptors-Madurai for Demo Class.

1. S.PRIYADHARSHINI
II B.ED YEAR PHYSICAL SCIENCE

2. HEAT

4. TRANSFER OF HEAT
If heat energy is applied to any substance , it will be
transferred from one part of the substance to
another part .
It takes place in different ways depending on the
state of the substance. They are
i. Conduction
ii. Convection
iii. Radiation

5. CONDUCTION
It is a process of heat transfer in solids from
the region of higher temperature to the region
of lower temperature without the actual
movement of the atoms or molecules.
CONDUCTION IN DAILY LIFE :
 Handles of cooking utensils are made up of
plastic or wood because they are poor
conductors of heat.
 When we iron dresses , heat is transferred
from iron to the cloth.

6. CONDUCTION
 take some hot water in a cup and
put a silver spoon in it. Leave the
spoon and now touch the other end
of the spoon. We feel heat in the
spoon. This is because heat from
water is passed to spoon. In solid
particles atoms are arranged very
closely . Hot water molecules
which vibrating transfer the heat
energy to the atoms in the spoon
and make vibrate . Those atoms
make other atoms to vibrate and
thus heat is transferred to the other
end of the spoon .

7.  Take some water in a vessel
and then heat it on the
stove.now touch the surface
it will be cold and after it will
be hot. This is because
water get heated the water
molecules at the bottom
gain heat and move upward
and molecules at the top
comes down and get
heated.
CONVECTION

8. CONVECTION
 Form of heat transfer from places of high
temperature to places of low temperatures by
the actual movement of the molecules is
called as convection. It takes place in solids
and liquids.
CONVECTION IN DAILY LIFE
 Formation of sea and land breeze is due to
convection
 Wind blows from one region to the other by
the by convection.

9.  Radiation is a third form of
heat transfer.
 In this process heat can
be transferred through
empty space even through
vaccum.
 Heat energy fro the earth
sun reaches the earth by
radiation process.

10. RADIATION
 It is defined as the way of heat transfer from one
place to another in the form of electromagnetic
waves
RADIATION IN DAILY LIFE
 .cooking vessels bottom are painted black so that it
absorbs heat.
 During summer white colored dresses are preferred
than black color dresses because they reflects
heat.

11. CALORIMETERY
 The technique used to measure the amount
of heat involved in a physical or a chemical
process is known as calorimetry.
 TEMPERATURE:
It is a physical quantity which expresses
whether an object is hot or cold. It is
measured with the help of thermometer.
There are 3 scales to measure temperature:
*celsius scale * fahrenheit scale * kelvin
scale

12. UNITS OF HEAT
 the unit of energy in SI system is joule.
 Heat is also measured in joule.
 It is expressed by the symbol J.
 The most commonly used heat is calorie.
 One calorie is the amount of heat energy
required to raise the temperature of 1 gram of
water through 1 degree celcius.
 The relation between one calorie and joule is 1
calorie=4.186J.

13. CALORIMETER
 A calorimeter is a device used to measure
the amount of heat gained or lost by a
substance.
 It consists of vessel made up of metals like
copper or aluminium which are good
conductors of heat and electricity.

14. CONSTRUCUTION OF CALORIMETER
 Metallic vessel is kept in an
insulating jacket to prevent
heat loss.
 There are 2 holes. Through
one hole thermometer is
inserted to measure
temperature.
 A stirrer is inserted through
another hole for stirring the
content.the vessel is heated
by passing current through the
heating element. Using this
device we can measure the
heat capacity.

15. THERMOSTAT
 It is a device which
maintains the temperature
of a place or an object .
 The word is derived from
greek word thermo
meaning heat and static
meaning the same. It turns
on appliance or circuit on
or off when an particular
temperature is reached.
De vices with thermostat
are water heater, AC,
fridgde

16. THERMOFLASK
 It is an insulating storage
vessel that keeps its contents
hotter or cooler than the
surroundings for a longer
time.
 It is mainly used to enhance
the storage period of a liquid
by maintaining a uniform
temperature and avoiding the
possibility of getting a bad
taste

17. WORKING OF THERMRMOFLASK
 It has double walls which are evacuated.
 It is silvered inside. The vaccum between the
two walls prevents heat being transferred from
the inside to the outside by conduction and
convection.
 With the little air between the walls there is
almost no transfer of heat from the inner wall to
the outer wall.
 Conduction occurs at the point where two walls
meet at the top of the bottle.
 the silvered walls reflect radiated heat back to
the liquid in the bottle .

18. TEACHING AIDS

20. THANK YOU