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Chapter 5 – Earth’s
Weather
Lesson 2 –
Air Currents and Wind
© Brent Coley 2010 | www.mrcoley.com
Why are temperatures
different?
• Sunlight hits the Earth at
different angles.
180°
135°
90°
equator
Why are temperatures
different?
• Direct beams of light (90°)
create more heat than slanted
180°
beams.
135°
90°
equator
Why are temperatures
different?
• Places near the equator get
more direct sunlight, so they are
180°
warmer than
places to
135°
the north
90°
equator
or south.
How is air pressure different
over land and water?
• sea breeze: air moves from high
pressure (over water) to low
pressure (over land).
• land breeze: air moves from high
pressure (over land) to low
pressure (over water).
What are global winds?
• As temperature goes up, air
pressure goes down.
• As temperature goes down, air
pressure goes up.
What are global winds?
• Air always moves from areas of
high pressure to areas of low
pressure.
High
Just think of rolling a
ball on a slope – it
goes from high to low!
Low
What are global winds?
• convection: the rising and
falling of gas or liquid in a
continuous cycle
• When convection happens in
air, it forms winds.
• global winds: winds that blow in
predictable directions over long
distances
All images courtesy of Microsoft
Office Online.