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Heat Transfer
Friction
 Resistance, takes place when two objects rub together
Brownian Motion
 The jiggling motion that particles do
 Robert Brownian was the first to realize this
 Particles are constantly moving and vibrating
 Movement is caused by the collision of particles
Heat
 Heat is also known as thermal energy
 Kinetic energy is the form of energy associated
with movement, it measures how much energy of
motion particles have
 Temperature is the average kinetic energy of all
particles in an object
 Heat is the sum of the kinetic energies of all
particles in an object
 See page 86
Temperature vs. Thermal Energy
 Temperature = A measure of the average energy of the
particles in a material.
 Thermal Energy/Heat = The total energy of all the
particles in a material.
What is the difference??
Transferring Energy
 There are 3 main ways to transfer energy
 1) Radiation
 2) Conduction
 3) Convection
Heat Transfer
 Heat flows from a hot to a cold object until they
are at the same temperature
 Conduction is the transfer of heat via contact
 When you place a cool pot on a hot stove, the
particles of the stove have more kinetic energy
than the particles of the pot.
 When the two contact each other, the hot stove
looses kinetic energy to the pot.
 The better the conductor, the more rapidly heat
will transfer.
 Convection is the up and down movement of gases
and liquids caused by heat transfer. Hot air/liquids are
less dense, and cold air/liquids are more dense which
creates convection current.
 Radiation is produced by wave that travel through
space. When the waves come in contact with an object,
the waves transfer the heat to that object.
Convection and Weather
 Cottages are often located along lake shores
because the air is cooler during the day and
warmer at night
 At night, the air over the water cools slower then
the air over land
 Warm air then moves from over the water to over
land, keeping the temperature warm
 During the day cool air from the water moves
toward the land, lowering the temperature on land
Sea and Land Breezes
 Warm air rises, cool air sinks
 All winds start via convection currents
 Land and sea breezes start near a shoreline
 The suns rays are absorbed by the sea and the land
at different rates, water heats slowly and takes
longer to cool than air
 Page 94 diagrams
Oceans and Climates
 Oceans store thermal (heat) energy
 Areas around oceans usually do not experience
extreme weather changes
 In cool weather oceans release heat, while the
ocean temperature remain relatively constant
 When the air is warm, warm air flows into the
water, warming the water
 When the air is cool, heat flows from the ocean to
the air, warming the air
How Oceans Affect Climate Activity
Climate Pattern Statistics for Five Canadian Cities
City
Mean January
Temperature in Celsius
Mean July Temperature in
Celsius
Calgary, Alberta
-11
17
Quebec city, Quebec
-12
19
Winnipeg, Manitoba
-18
20
Regina, Saskatchewan
-17
19
Vancouver, British
Columbia
2
17
Graph
Mean
Temperature
in Celsius
City
Ticket out the DOOR
 Convection happens because…
a) Hot atoms are lighter than cold atoms, so cold atoms rise.
b) Fluids become less dense as they are heated, and
c)
d)

a)
b)
c)
d)
differences in density cause currents.
Hot atoms rise to the top of all solid materials.
Radiation cannot be absorbed or emitted by some
objects.
Water touching the bottom of the hot pan begins to heat
up; this is an example of ?
Conduction
Convection
Radiation
None of the above
Heat Transfer
 Materials in your home are designed to transfer
heat or prevent the transfer of heat
 Pots facilitate transfer, where as insulation
prevents it
 When an oven is turned on convection currents
move heat
 As oven walls get hot, heat is radiated around the
oven
Getting Rid of Heat
 Page 101, how does heat transfer in a refrigerator work?