Conduction, Convection,
Radiation
Unit 9/Day 3
How does heat energy move?
• Heat always moves from a warmer
place to a cooler place.
(Hot
Cold)
• Heat transfers in three ways:
– Conduction
– Convection
– Radiation
What is Convection?
• Convection is the transfer of heat by the actual movement of
the warmed matter.
• Heat leaves the coffee cup as the currents of steam and air
rise. Convection is the transfer of heat energy in a gas or liquid
by movement of currents. (It can also happen is some solids,
like sand.)
• Consider this: convection is responsible for making
macaroni rise and fall in a pot of heated water. The warmer
portions of the water are less dense and therefore, they
rise. Meanwhile, the cooler portions of the water fall
because they are denser.
So… then what is Conduction?
• Conduction is the transfer of energy through matter from
particle to particle. Also can be referred to as the transfer and
distribution of heat energy.
• For example, a spoon in a cup of hot soup becomes warmer
because the heat from the soup is conducted along the spoon.
• Conduction is most effective in solids-but it can happen in fluids.
• Fun fact: Have you ever noticed that metals tend to feel
cold? Believe it or not, they are not colder! They only feel
colder because they conduct heat away from your hand.
You perceive the heat that is leaving your hand as cold.
Why does metal feel colder than
wood if they are in the same
room?
Metal is a conductor and wood is an insulator.
• Metal conducts the heat away from your hands.
Wood does not conduct the heat away from your
hands as well as the metal, so the wood feels warmer
than the metal.
…and what Radiation?
• Radiation: Electromagnetic waves that
directly transport ENERGY through space.
Sunlight is a form of radiation that is radiated
through space to our planet.
Pop Quiz Question!
• If a cup of coffee and a red popsicle were
left on the table in this room what would
happen to them?
• Why?
Do colors matter?
• Yes!
• Heat excites a black (dark) surface more
than a white (light) surface. Black is a good
absorber and a good radiator.
• Think of black as a large doorway that allows
heat to pass through easily. In contrast, white is
a poor absorber and a poor radiator of energy.
White is like a small doorway and will not allow
heat to pass easily.
Draw 2 examples of conduction.
Draw 2 examples of convection.
Draw 2 examples of radiation.
Once complete…
compare with a partner.
1. Which of the following is not a
method of heat transfer?
A. Radiation
B. Insulation
C. Conduction
D. Convection
In which of these are the particles
closest together?
A. Solid
B. Liquid
C. Fluid
D. Gas
How does heat reach the Earth
from the Sun?
A. Conduction
B. Convection
C. Insulation
D. Radiation