HEAT
What is Temperature?
 Temperature is the
average kinetic
energy of the
particles of an
object.
 As temperature
increases , kinetic
energy of the
particles increases.
How is temperature related to the
movement of the particles?
 The faster the
particles of an
object move, the
higher the
temperature of
the object.
Which particles are moving faster,
those in a cup of hot tea or iced
tea?
What is thermal expansion ?
Thermal
expansion is the
increase in the
volume of a
substance due
to an increase in
temperature .
What is the official SI unit of
temperature?
Kelvin
Temperature conversion formulas
 Celsius to Fahrenheit:
oF
= (9/5 * oC) + 32
 0F
 Fahrenheit to Celsius: oC = (5/9) * (oF – 32)
oF  0C
 Celsius to Kelvin: K = oC + 273
oC  K
 Kelvin to Celsius: oC = K – 273
K  oC
oC
Fill the missing blanks using the
previous
oF
oC
Water boils
100o
Body Temperature
37o
Room Temperature
Water freezes
Absolute zero
K
68o
0o
0
What is absolute zero?
 The lowest
temperature on
Kelvin scale
(zero Kelvin)
 At this temperature
particles stop
moving.
What is heat?
 Heat is the transfer of
energy between two
objects that are at
different temperatures.
 When two objects of
different temperature
come in contact,
energy is always
transferred from the
higher temperature to
the lower
temperature.
What is thermal energy?
 Thermal energy is
the total energy of
the particles that
make up a
substance. It is
measured in
Joules.
 Which one has
more thermal
energy?
What is thermal equilibrium?
 Energy is transferred from
the higher temperature object
t o the lower temperature
object until both objects
reach the same temperature.
What are conductors?
Conductors
are substances
that conduct
thermal
energy.
What is an insulator?
 An insulator is a substance that does not conduct
thermal energy .
How is heat transferred?
Heat and temperature
change
Thermal conductivity
 The rate at which a substance conducts thermal
energy.
Specific heat capacity
 The amount of energy
needed to change the
temperature of one Kg of a
substance by one degree
Celsius.
Specific heat capacity of different materials:
Materials
Specific heat capacity
Silver
234
Copper
387
Glass
837
Wood
176
Steam
2010
Ice
2090
Aluminum
899
Water
4184
Matter and heat
States of matter
 Three states of matter: solid ,
liquid and gas.
 Heat engines
heat technology
a. A machine that uses
heat to do work.
b. Heat engines burn fuel
to produce thermal
energy in a process
called combustion.
c. There are two types of
heat engines: external
combustion and
internal combustion
heat engines.
 External combustion:
fuel is burned
outside the engine.
 Internal combustion:
fuel is burned inside
the engine.
Cooling system
Question:
 Cooling systems are used
to transfer thermal energy
out a particular area so
that is feels cooler.
 Will leaving the
refrigerator door open on a
hot day help to cool the
kitchen?