Download Heat Transfer

3 Types of Heat Transfer
Heat Transfer
 The word “transfer” means to carry across.
 When heat transfer occurs, the energy is carried through or
across from one solid, liquid, or gas to another
 3 types of heat transfer
 Conduction
 Convection
 Radiation
When the energy of the sun hits an object,
some of the sun’s energy is transferred to
the object’s molecules, heating them. When
heat is transferred by invisible waves is this
is called radiation. When a person touches
that warmed object then some of the energy
in the object’s molecules is transferred to
the molecules in the person’s skin. This
transfer of heat is called conduction. If the
heated molecules move to another location,
this is called convection.
Transfer of Heat Energy Activity
 Students pretend to be the molecules in an object
 Stand in a circle and hold hands
 Student will be touched to indicate that the sun is warming
this molecule.
 That person clenches his right hand around the left hand of
the person whose hand (s)he’s holding.
 That triggers this individual to then squeeze his/her right
hand, pressing on the left hand of the person whose hand
(s)he’s holding.
Conduction
 Transfer of heat through a solid or between
a solid and another solid, a liquid or a gas
that is in contact with it.
 Occurs in only one direction (from warmer
to cooler)
Convection
 Transfer of thermal energy by moving
particles in fluids-liquids and gases
 Circular pattern of moving particles
(convection current)
 Heat transfers from hotter region to cooler
region
Radiation
 Does not involve the movement of particles
 Transfer of energy by invisible waves given off by the
energy source
 Heat transferred by invisible waves is called infrared
waves
 All hot solids, liquids, and gases radiate invisible heat
waves
 When invisible waves of radiant energy come into
contact with a solid, the particles in the solid vibrate
faster
 Coloured solids absorb and reradiate infrared waves, but
transparent solids, liquids, and gases allow waves to pass
easily through them
Heat Transfer Song
 http://www.educationalrap.com/song/radiation-
conduction-convection.html
Heat Transfer Summary