The Transfer
of Heat
Thermal Energy
• Energy is the ability to make things move or
change.
• All matter (anything with mass that takes up
space) is made up of tiny particles that are
always moving.
• Thermal energy is the energy of the moving
particles. This energy is felt as heat.
Thermal Energy = Heat
Heat
• Heat ALWAYS moves from a warmer object to
a cooler one. This movement is called heat
transfer.
• As heat moves into an object, it becomes
warmer. As heat moves out of an object, it
becomes cooler.
Heat Transfer
• When a freshly made
cup of coffee is sitting on
a counter, it will lose
heat because the air
around it is cooler than
the coffee.
• When an ice cube is
sitting on a table, the
warmth in the air will
transfer into the ice
cube, melting it.
Heat Transfer
• There are 3 ways that heat can transfer to
other objects. These methods of transfer are
called conduction, radiation, and convection.
Conduction
• Conduction is the
transfer of heat between
things that are touching.
Examples:
• Hands are warmed when holding a hot
mug of cocoa
• A hot stove burner warms a pot sitting
on it.
• When two things that
are touching have
different temperatures,
heat will move from the
warmer object to the
cooler one.
• Can you think of some other examples?
Conductors
• Conductors are objects that allow
heat to move through them easily.
• Metals are good conductors
because they allow heat to move
through them easily. Examples of
metals include iron, silver, copper,
aluminum, and stainless steel.
• For example, if you were at a
campfire and you put a stick in the
fire, your hand would not burn.
Wood is not a good conductor. If
you left a metal spoon in a hot pot
on the stove and held the spoon,
your hand would burn.
Convection
• Convection is the
transfer of thermal
energy through
liquids or gases.
• Warmer air and
water rises and
cooler air and water
sinks. This creates a
convection current.
Click the picture below for
a convection
demonstration.
Radiation
• Radiation is the transfer of energy through
electromagnetic waves.
• Radiation from the sun heats objects on Earth.
Heat travels from fire to objects through
radiation as well.
Thermal Energy Review