Energy Transfer and
Interactions of Matter and
Energy
6.P.3
Question
• If a cup of hot coffee and a red popsicle were
left on the table in this room what would
happen to them? Why?
• The cup of coffee will cool until it reaches
room temperature. The popsicle will melt and
then the liquid will warm to room
temperature.
In this lesson you will revisit:
• The way in which heat behaves.
• The energy transfer methods:
– conduction
– convection
– radiation
• How to reduce heat losses from your home.
Let’s Review: Measuring Heat
Heat is measured with a thermometer.
Celsius
• Freezing: 0°
• Boiling: 100 °
Fahrenheit
• Freezing: 32 °
• Boiling: 212 °
What Does Heating or Cooling Do to Materials?
Melting: Solid matter
changes its state to
liquid.
Freezing: Opposite
process of melting is
called freezing.
Liquid matter loses heat
and changes its state to
solid.
Boiling: Liquid matters
gain heat and change
their states to gas.
Energy can be transferred from one
system to another in different ways:
• Thermally: when a
• Electrically: when
warmer object is in
electrical source
contact with a cooler
such as a battery or
one
generator is
connected in a
• Mechanically: when
complete circuit to
two objects push or
an electrical device
pull on each other
over a distance
• Electromagnetic
Waves
Molecules in Motion:
Thermal energy
• The motion of
molecules produces
heat
• The more motion,
the more heat is
generated
• Thermal energy is
transferred through
a material by the
collisions of atoms
within the material.
Heat Transfer
• The movement of heat from a warmer object
to a cooler one.
• Heat flows through materials or across space
from warm objects to cooler objects, until
both objects are at equilibrium (balanced).
Heat Transfer
• Heat always moves from a warmer place to a
cooler place.
• Hot objects in a cooler room will cool to room
temperature after the hot object transfers some of
their heat to the cold object.
• Cold objects in a warmer room will heat up to room
temperature.
Heat Transfer Cont.
• Therefore warm things lose heat and cool
things gain heat until they are all at the same
temperature.
• Example: Ice cube is put in a glass of warm
water. Ice cube gains heat from the water and
the warm water loses some heat.
• Eventually the ice will melt and the water will
be at an even temperature
Heat Transfer Methods
• A warmer object can warm a cooler object by
contact (close/touching) or at a distance (far
away)
• Conduction
• Convection
• Radiation
www.teachersdomain.org/asset/lsps07_int_he
attransfer/
Conduction
• Conduction involves the
transfer of heat through
direct contact
• Heat travels through solids
primarily by conduction.
• Over time, thermal energy
tends to spread through a
material and from one
material to another if they
are in contact (conduction)
Conduction
When you heat a metal strip at one end, the heat
travels to the other end.
As you heat the metal, the particles vibrate, these
vibrations make the adjacent particles vibrate, and
so on and so on, the vibrations are passed along
the metal and so is the heat. We call this?
Conduction
• Takes place in liquids
and gases as
molecules move in
currents
• Heat rises and cool
settles to the bottom.
• It continues in an up
and down movement:
warm rising and cool
sinking (currents).
• These currents are in
air, water, and other
fluids
Convection
Water movement
Cools at the
surface
Cooler water
sinks
Convection
current
Hot water
rises
Cold air sinks
Where is the
freezer
compartment
put in a
fridge?
It is put at the
top, because cool
air sinks, so it
cools the food on
the way down.
Freezer
compartment
It is warmer at
the bottom, so
this warmer air
rises and a
convection
current is set up.
Convection questions
Why does hot air rise and cold air sink?
Cool air is more dense than warm air, so the
cool air ‘falls through’ the warm air.
Why are boilers placed beneath
hot water tanks in people’s homes?
Hot water rises.
So when the boiler heats the water, and the hot
water rises, the water tank is filled with hot
water.
Radiation
• Radiation is energy that travels across distances in
the form of electromagnetic waves.
• Heat is transferred through space
• Energy from the sun being transferred to the Earth
• Light and other electromagnetic waves can warm
objects.
• How much an object’s temperature increases
depends on:
– how intense the light striking the surface
– how long the light shines on the object
– how much light is absorbed.
RADIATION
How does heat
energy get from the
Sun to the Earth?
?
There are no
particles between
the Sun and the
Earth so it
CANNOT travel by
conduction or by
convection.
• The sun is a major source of
energy for changes on the
earth’s surface.
• The sun loses energy by
emitting (releasing) light.
• A tiny fraction of the light
reaches the earth,
transferring energy from the
sun to the earth.
• The sun’s energy arrives as
light with a range of waves:
– Infrared Light: longer wave
– Visible Light: visible wave
– Ultraviolet Light: shorter wave
Radiation
Radiation
Radiation travels in straight lines
True/False
Radiation can travel through a vacuum
True/False
Radiation requires particles to travel
True/False
Radiation travels at the speed of light
True/False
ELECTROMAGNETIC SPECTRUM
Radiation questions
Why are houses painted white in hot
countries?
White reflects heat radiation and keeps the house cooler.
Why are shiny foil blankets wrapped
around marathon runners at the end of a
race?
The shiny metal reflects the heat radiation from
the runner back in, this stops the runner getting
cold.
Heat Transfer Song
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
• Please create your own definitions for the
following words based on the picture.
• Convection
• Conduction
• Radiation
Copyright © 2010 Ryan P. Murphy
1.
Which of the following is not a
method of heat transfer?
A.
Radiation
B.
Insulation
C.
Conduction
D.
Convection
2. In which of the following are
the particles closest together?
A.
Solid
B.
Liquid
C.
Gas
D.
Fluid
3. How does heat energy reach
the Earth from the Sun?
A.
Radiation
B.
Conduction
C.
Convection
D.
Insulation
4. Which is the best surface for
reflecting heat radiation?
A.
Shiny white
B.
Dull white
C.
Shiny black
D.
Dull black
5. Which is the best surface for
absorbing heat radiation?
A.
Shiny white
B.
Dull white
C.
Shiny black
D.
Dull black