HEAT
TRANSFER
Radiation,
Conduction
&
Convection
HEAT ENERGY
The source of heat for our planet
is the sun.
The sun’s energy moves through
space, then through the
atmosphere and finally reaches
earth’s surface.
THIS HEAT IS TRANSFERRED THROUGH THE
ATMOSPHERE BY THE FOLLOWING 3 MECHANISMS:
1. Radiation
2. Conduction
3. Convection
RADIATION
Transfer of heat by means of waves
that do not require a medium or
particles to transfer the heat.
Example: heat from a campfire,
candle’s light, visible light
THE OTHER
METHODS OF
ENERGY TRANSFER
REQUIRE
PARTICLES OF
MATTER .
CONDUCTION
Transfer of energy through the
collision of particles
Examples: a cast iron skillet on the
stove, mug of coffee and the mug
becomes hot, walking on hot
pavement in the summer, melting an
ice cube in your hand
CONDUCTION
conduction always causes heat to be
transferred from the warmer mass to
the colder
CONVECTION
Heat transfer in a gas or liquid by
the circulation of currents from one
region to another.
Examples: boiling water, steaming
cup of tea, radiator (puts warm air
out the top and draws cool air in the
bottom)
**NOTE**
Convection – transfers energy
vertically
Advection – transfers energy
horizontally
LET’S TAKE A MINUTE
TO TRY SOME
DEMONSTRATIONS TO
SHOW THESE TYPES
OF ENERGY
TRANSFER
DEMONSTRATIONS
 Record your observations in the chart provided
Demonstration
1)
1)
1)
Observations: what did you
see happen?
Type of Heat Transfer
EVERYDAY
EXAMPLES OF
RADIATION,
CONDUCTION &
CONVECTION…
BUT……
HOW DO RADIATION,
CONDUCTION &
CONVECTION AFFECT
OUR CLIMATE?
HOW DOES RADIATION AFFECT OUR
CLIMATE?
Radiation - The energy that comes
from the sun reaches us by
radiation, we feel this on a daily
basis.
HOW DOES CONDUCTION AFFECT OUR
CLIMATE?
Conduction - although conduction
occurs most easily in metals such as
steel, it also occurs to a small extent
in substances on Earth’s surface
such as rocks, sand, soil and water.
HOW DOES CONVECTION AFFECT OUR
CLIMATE?
Convection - Since weather systems
depend on the movement of
particles in the atmosphere and
oceans, convection and advection
help in understanding weather
systems.
HOW DOES CONVECTION AFFECT OUR
CLIMATE?
Oceanic circulation - Warm water
around the equator circulates
towards the poles and the cooler
water at the poles moves towards
the equator.
This is an example of convection
REFLECTION AND ABSORPTION OF
ENERGY
When electromagnetic waves for the Sun
reach Earth, some are reflected off the
atmosphere and clouds back into space;
some pass through the atmosphere and
bounce off Earth back into the
atmosphere; and some get absorbed by
the atmosphere, the ground or the water
at the surface.
Any object of material that absorbs
energy and becomes warmer is
called a heat sink.
(A heat sink holds energy in a similar
way to how a kitchen sink holds
water).
Oceans are good heat sinks.
When solar energy hits water, the water
begins to move (convection activity) and
transfers energy hundreds of meters deep into
the oceans.
Soil and rocks are poor heat sinks because
heat is conducted very slowly into these
materials.
An important property of all
substances is their heat capacity.
Heat Capacity  the measure of
how much heat a substance requires
to increase its temperature or how
much heat it releases as its
temperature decreases.
Soil and rock are poor heat sinks;
their heat capacity is low.
Water on the other hand has a very
high heat capacity.
EARTH’S ENERGY BALANCE
Different types of electromagnetic
energy are emitted from the sun, and
they all have different effects when they
reach the Earth’s surface.
Without all the energy; plants would not
grow, and the land, water and air would
not stay warm enough for us to survive.