Download 6.9B verify through investigations that thermal energy moves in a

6.9B verify through investigations that thermal energy moves in a predictable
pattern from warmer to cooler
6.5B recognize that a limited number of elements comprise the largest portion
of oceans and atmosphere
8.10A recognize that the Sun provides the energy that drives convection
within the atmosphere and oceans, producing winds and ocean currents
• How do they work?
• Due to the background color of this ppt, the
notes you need to take are in yellow!
• Surrounding the Earth is a gases envelope, the
atmosphere
A. It is mainly composed of a few limited
elements:
• Nitrogen ~78%
• Oxygen ~21%
• Argon, Carbon, Neon, Helium, Hydrogen, &
Krypton ~1%
B. Is a complex and dynamical, physical and
chemical system.
• Dynamical: the processes of evaporation,
condensation, precipitation
• Physical: the transfer of heat from the Sun to
the Earth’s surface
• Chemical: the transformation and production
of gases, such as ozone through chemical
reactions of atmospheric gases.
• While the
atmosphere
extends
hundreds of
kilometers,
more than half
of its mass is
about 6 km
above the
surface, in the
troposphere
• If more than half of the mass is located in the
troposphere, does this mean that air has
weight?
Yes!
• Think back to when we learned about the Sun
heating the Earth.
• Do the sun’s rays hit the Earth evenly?
• The atmosphere to be
heated differently
• The land and water to
be heated differently
• All 3 of these things:
solid (land), liquid
(water) and gas (air)
have different
densities and
therefore hold and
pass along heat
differently!
The more dense an object is, the more tightly packed
the atoms are. Less dense objects have fewer
molecules in the same amount of space.
Can density “change”?
Yes!
As things such as air heat up, the molecules start
to move and need more space. This movement
of the molecules increases the volume and
therefore less matter is contained in the same
space.
This is why hot air rises!
•Wind patterns are
caused by air’s
properties:
•Cool air sinks
•Warm air rises
•Density changes as
the temperature
changes!
•Forms convection
currents
• Wind is the movement of
air as a result of different
air pressure
• The greater the pressure
difference, the stronger the
wind
• The air around you has
weight, and it presses
against everything it
touches.
• That pressure is called
atmospheric pressure, or
air pressure.
• It is the force exerted on a
surface by the air above it
as gravity pulls it to
Earth.
• pressure = force/area
• Wind (air) always moves from high pressure to low
pressure (this key, underline it!!!)
• Air moves because of an imbalance in the forces acting
on the air molecules.
• Wind is the atmosphere's way of trying to bring the
interaction of these forces into a balance; an
equilibrium.
• However, the factors that cause the imbalance are
constantly changing so the balance is never achieved,
so the air molecules move, which is wind.
• Watch the wind move today!
• http://hint.fm/wind/
Latitude is on the left and Longitude is on
the right
A. Wind travels
in “Pressure
belts”, which are
low or high
pressure areas
which lie parallel
to latitudes.
• On the earth's surface, there are seven pressure
belts. They are the Equatorial Low, the two Subtropical Highs, the two Sub-polar Lows, and the two
Polar Highs.
• There is a pattern of alternate high and low
pressure belts
• This is due to the spherical shape of the earth—
different parts of the earth are heated unequally.
• The winds also do not flow in straight lines, but
curve around the Earth.
• Global winds do not
blow in straight lines
• The earth rotates as
wind blows, making it
seem as if the winds
are curving
• Called the Coriolis
effect
The Coriolis Effect
Coriolis Animation
• Local winds- generally move short
distances and can blow from any direction.
Air Cools Down
Cold Air Sinks
Warm Air Rises
Warm Air Rises
Wind Blows Toward Coast
Air Cools Down
Cold Air Sinks
Wind Blows Away from the Coast
•During the day, the land
heats up more quickly
than the sea. Above the
land, warm air rises and
the wind blows toward
the coast.
•At night, the land cools
down quickly while the
sea stays warm. Above
the sea, warm air rises
and the wind blows away
from the coast.
•Global winds- are part
of a pattern of air flow
that moves across the
Earth.
•Winds carry heat north
from Earth’s equator
•Winds carry colder air
south toward the
equator.
• Coriolis and other factors combine to produce a
pattern of wind belts around the earth
• Major wind belts:
• Trade winds
• Westerlies
• Easterlies
• The names of the
types of winds on
the next few slides
are in red.
• Then draw the
direction of the
winds, using
arrows
•Called trade winds because
early sailors used the winds to
sail from Europe to America
•Blow at 30o latitude to the
equator.
•Label the equator, and the
trade winds.
•The wind movement arrows
are done for you for this one
•Between 30o and 60o
latitude. Flows towards
the poles. Helped ships
return to Europe.
•Blows from west to east-WESTERLIES
• Winds are turned toward
the east by Coriolis effect
•Label the westerlies and
draw arrows on your globe
•Between the poles and
60o latitude.
•Cold air near poles sinks
and flows back toward
lower latitudes
•Coriolis shifts these winds
to west
•Wind goes from East to
west—EASTERLIES
•Label on your globe!
•Near equator, between 0-30
degrees latitude (usually
between 5° north and 5°
south of the equator)
•Rising air, low pressure
•Cool air moves into area,
warmed rapidly, and rises
•Warms so fast, air
doesn’t really move (no
breeze) before it rises
again.
• Sailors noticed the stillness of the rising
(and not blowing) air near the equator
and gave the region the depressing name
"doldrums."
•Between about 30°
to 35° north and 30°
to 35° south
•Weak winds
•Forms a belt of
calm air
•Contributes to
deserts in this area
• This area of subsiding dry air and high pressure results
in weak winds. Tradition states that sailors gave the
region of the subtropical high the name "horse
latitudes" because ships relying on wind power stalled;
fearful of running out of food and water, sailors threw
their horses and cattle overboard to save on provisions.
• (It's a puzzle why sailors would not have eaten the
animals instead of throwing them overboard.)
• So wind moves around on Earth,
especially due to the uneven heating
received from the Sun
• How does this really effect Earth, besides
WIND?
• Climates!
•Most rainforests
are near the
equator because
this is where the
air is rising
(because it is
heated), creating
clouds and rain.
o
Most deserts are at 30 N and S Latitude
because the air is sinking, loosing the
moisture, drying it out.
• Winds animation (explains rainfall and biomes
too)
• http://www.kevinflint.org/ppt/chap5/Animati
ons/global_circ_anim.html