Transcript Convection and Radiation

Convection and Radiation
Chapter 12
Heat
Lesson 2 continued
My room!
Convection: Going with the flow
• A convection current is a
pattern of
.
Radiator
• What is a fluid?
• In a room heated by a
radiator, where is the
warmest air located? Where
is the coldest air located?
• How do convection currents
affect weather?
• Why is the 8th floor of my
dorm hotter than the
bottom floors?
How do convection currents
affect weather?
The wind we feel outside is
often the result of convection
currents. You can understand
this by the winds you feel near
an ocean. Warm air is lighter
than cold air and so it rises.
During the daytime, cool air
over water moves to replace
the air rising up as the land
warms the air over it.
Think: Convection  Winds
Cause  Effect
Why is the 8th floor hotter than
the bottom floors?
Whew! It’s hot
up here!
It feels nice
down here!
GOING WITH THE FLOW
Convection is all about flow. It needs something flowing
to carry heat – fluids – liquids or gases. Because of
convection currents, all the water in a tea kettle gets
heated, not just the water at the bottom closest to the
stove.
Remember: Heat RISES!!!
WHY? Think density
Radiation: Riding the Waves
• Radiation is
that is sent
out in
.
• How is radiation
different from
conduction and
convection?
• Use radiation to explain
how a greenhouse might
work. (Hint: pg. 358 in
textbook)
• Why do you feel cooler
the farther away you
move from a fire?
Greenhouse
The sun’s RAYS RADIATE to Earth!
It’s cold over
here! Can I
come closer
to the fire?
No! You’re
weird!
Ahhh….
that sun
feels
nice!
Putting it all together
• Give an example of how
conduction, convection,
and radiation work together.
Putting it all together
• Take out your Venn Diagrams from
yesterday (where we compared
conductors and insulators).
• Turn to the back.
• Work with a partner to fill in the blanks
in the diagrams: (there are 2)
– Conduction – think TOUCH
– Convection – think FLOW
– Radiation – think FEEL
CONDUCTION
(TOUCH)
CONVECTION
(FLOW TO TOP)
RADIATION
(FEEL)
CONVECTION
(FLOW)
CONDUCTION (TOUCH)
RADIATION (FEEL)
Exit Ticket
• Why does a car or person get hot
sitting out in the sun?