Convection Currents
and the Mantle
• OBJECTIVES:
– Explain how heat is transferred
– Identify what causes convection currents
Radiation
• The transfer of energy
through empty space
• Examples:
-Sunlight
-Open flame
Conduction
• Heat is transferred by
direct contact of
particles of matter
• Heat travels from hot
to cold
• Examples:
– Hot frying pan, Fire
poker stick
Convection
• The movement of a fluid,
caused by differences in
temperature and density,
that transfers heat from one
part of the fluid to another
• Examples:
-Heating water
-Mantle in the
Asthenosphere
-Air --wind
Checkpoint-1
• What are the three types of heat transfer?
ANSWER-1
• RADIATION
• CONDUCTION
• CONVECTION
Checkpoint-2
• Describe how convection currents form?
ANSWER-2
• The heating and cooling of a fluid changes in a
fluid’s density, and the forces of gravity combine
to set convection currents in motion.
Checkpoint-3
• In general, what happens to the density of a
fluid when it becomes hotter?
Answer-3
• In general, when a fluid is heated, its
density decreases. --i.e.steam and ice
Checkpoint-4
• What happens to convection currents when
a fluid reaches a constant temperature?
ANSWER-4
• When a fluid reaches a constant
temperature, the convection currents stop.