Transcript Winds - Fort Bend ISD

Warm Up
1. If warm air rises, where on the Earth do you
think this process would happen the most?
2. Rising warm air transports heat energy by
A.
B.
C.
D.
Conduction
Convection
Radiation
Condensation
Winds
p. 472 – 477 in 6th grade
textbook
What Causes Wind?
• A wind is the horizontal movement of air from
an area of high pressure to an area of low
pressure.
• All winds are caused by differences in air
pressure.
What Causes Air Pressure Differences?
Caused by
uneven
heating of
the Earth’s
surface
(direct and
indirect
light!)
Low Air Pressure
• Areas that get lots of heat on Earth’s surface
(EQUATOR) have hot air with low density 
low air pressure
High Air Pressure
• Areas that do not get a lot of heat (THE POLES)
have colder air with high density  high air
pressure
When Warm Air Meets Cold Air…
• Cold air is more dense and has a higher air
pressure, so it flows UNDER the warm air. This
forces the warm air to rise.
Talk About it - Checkpoint!
• Winds blow from areas of __________
pressure to areas of ________ pressure.
• High pressure - ___________ temperatures
• Low pressure - ____________ temperatures
Global Convection Currents
• Warm air rises at the equator (lower air
pressure here!)
• Cold air sinks at the poles (higher air pressure
here!)
• This pattern forms giant convection currents
in the atmosphere!
Global Winds
• Winds at Earth’s surface blow from the poles
(HIGH PRESSURE) to the equator (LOW
PRESSURE)
• Higher in atmosphere, winds blow from the
equator to the poles.
• The movement of air between the equator
and poles produces global winds.
This is a Simplified Diagram!
Talk About It
• Why does hot air rise in the atmosphere?
• Where does hot air rise on the Earth?
Giant Convection Currents
The Coriolis Effect
• Wind would blow in a straight line if the Earth
didn’t rotate
• Because the Earth rotates, wind blows in a
curved pattern
Coriolis Effect
The way
Earth’s
rotation makes
the winds
curve is called
the Coriolis
Effect.
The Coriolis Effect
• In the Northern Hemisphere, winds turn to
the right
• In the Southern Hemisphere, winds turn to
the left