Transcript CONVECTION CURRENTS AND THE MANTLE

CONVECTION
CURRENTS
AND THE
MANTLE
1. Heat is always transferred
from a WARMER substance
to a COOLER substance.
2. Cold is the absence of
HEAT.
3. There are three types of heat
transfer:
A. RADIATION –the transfer of
energy through EMPTY SPACE.
SUNLIGHT is radiation that
warms Earth’s surface.
Radiation takes place with no
DIRECT CONTACT between a
heat source and an object.
Other familiar
forms of
radiation
include the heat
you feel around
FLAME or
OPEN FIRE.
B. CONDUCTION – heat
transfer by DIRECT CONTACT
of particles of matter.
When a spoon sits in a hot pot of
soup, particles near the bottom of
the spoon VIBRATE faster as they
are heated, so they bump into other
particles and HEAT them.
Heat is transferred from the hot
SOUP and the POT to the
particles that make up the
spoon.
C. CONVECTION – heat
transfer by the MOVEMENT of
a heated fluid.
Heat particles of fluid begin to
FLOW transferring HEAT
ENERGY from one part of the
fluid to another one.
Convection is caused by
differences of TEMPERATURE
and DENSITY.
When a liquid is heated, the
particles move FASTER and
spread APART. This causes
density to DECREASE.
When a liquid is
cooled, the particles
move more SLOWLY
and settle together
MORE CLOSELY.
This causes density to
INCREASE.
A constant flow begins as cooler
soup CONTINUALLY SINKS to
the bottom and warmer soup
RISES.
4. WHAT ARE THE THREE
THINGS THAT SET
COONVECTION CURRENTS IN
MOTION?
- Heating and cooling of fluid
- Changes in the fluid’s density
- The force of gravity
5. HOW LONG DO CONVECTION
CURRENTS CONTINUE?
As long as heat is added
6. WHAT CAUSES A
CONVECTION
CURRENT TO STOP?
When all of the material
has reached the same
temperature.
7. Convection currents flow in the
Earth’s ASTHENOSPHERE. The heat
source for these currents is heat from
Earth’s CORE and from the MANTLE.