Chapter 16 Highlights At a Glance
Weather Factors p. 524-557
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Section 1 Energy in the Atmosphere p. 525-529
 Energy from the sun travels to Earth as
electromagnetic waves—mostly visible light,
infrared radiation, and ultraviolet radiation
affect Earth’s climate and weather.
 When Earth's surface is heated, it radiates
some of the energy back into the atmosphere in
the form of longer-wavelength radiation.
 Clouds help to keep the heat in at night.
 The greenhouse effect is the process by which
heat is trapped in the atmosphere by water
vapor, carbon dioxide, methane, and other
gases that form a “blanket” around Earth.
 Without the greenhouse effect, Earth’s
temperature would be a lot cooler.
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Section 2 Heat Transfer p.532-535
The energy of motion in the molecules of a
substance is called thermal energy.
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All objects have heat until they reach absolute
Zero (0˚Kelvin or -273˚C). At that temperature,
all molecular motion stops!
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Three forms of heat transfer—radiation,
conduction, and convection—work together to
heat the troposphere.
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Know how convections currents in the
atmosphere form and be able to explain it on a
diagram.
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As the warm air rises (less dense), air is
moving away from the ground so a Low
Pressure is formed.
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As cool air sinks (more dense), air is moving
towards the ground so a High Pressure is
formed.
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Section 3 Winds p.536-544
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All winds are caused by differences in air
pressure, which are the result of unequal
heating of Earth's surface due to the angle
energy from the Sun strikes Earth. (B/c Earth
is round, shortest route is at the Equator and get
longer as you move towards the Poles.
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Local winds are caused by unequal heating of
Earth's surface within a small area.
Know how and when a sea breeze and a land
breeze form.
Monsoons are seasonal winds.
Winds are named for the direction it is
coming from NOT where it is going.
The movement of air between the equator and
the poles produces global winds. These winds
blow in a constant predictable direction. There
are the Polar Easterlies, the Prevailing
Westerlies, the Trade Winds, and the Doldrums
(no wind due to all the air gradually rising) at
the Equator.
At the Equator there is Low Pressure due to
the heat making the air rise.
At the Poles, there is High Pressure due to the
cold dry air sinking.
The Coriolis Effect curves the winds right in
the N. hemisphere and left in the S. hemisphere
due to the spinning of the Earth to the east.
The Jet Stream is a fast moving river, 200400 kph, of air high in the troposphere flowing
from West to East. This has a huge control over
the weather systems below it in the U.S.
Section 4 Water in the Atmosphere p.545-550
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Relative humidity is the percentage of water
vapor in the air compared to the amount of
water vapor the air could hold. It can be
measured with a psychrometer.
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When Relative Humidity is 100%, it usually
is raining.
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Clouds of all kinds form when water vapor in
the air, cools and condenses and becomes
liquid water or solid ice.
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Meteorologists classify clouds into three main
types:
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Cumulus-fluffy fair weather clouds,
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Stratus-layers and covers the sky and as it
thickens will bring rain, snow, or drizzle, and
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Cirrus-high wispy clouds indicating a change
in weather is coming.
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The Dew Point is the temperature at which
water vapor condenses into liquid water or ice
crystals. This can tell you the temperature of
where the bottom of the cloud is & that is why
the bottom stratus and cumulus clouds are flat
and at the same level.
Vocabulary for Chapter 16
Copy into your Science Dictionary
Section 1 Energy in the Atmosphere p. 525-529
electromagnetic wave- A form of energy that can
travel through space.
radiation -The direct transfer of energy through
empty space by electromagnetic waves.
infrared radiation -A form of energy with
wavelengths that are longer than visible light.
ultraviolet radiation- A form of energy with
wavelengths that is shorter than visible light.
sea breeze -The flow of air from an ocean or lake
to the land.
land breeze- The flow of air from land to a body
of water.
monsoons -Sea and land breezes over a large
region that change direction with the seasons.
global winds -Winds that blow steadily from
specific directions over long distances.
Coriolis effect -The way Earth's rotation makes
winds in the Northern Hemisphere curve to the
right and winds in the Southern Hemisphere curve
to the left.
greenhouse effect- The process by which heat is
trapped in the atmosphere by water vapor, carbon
dioxide, methane, and other gases that form a
“blanket” around Earth.
jet streams- Bands of high-speed winds about 10
kilometers above Earth's surface.
Section 2 Heat Transfer p.532-535
humidity -A measure of the amount of water
vapor in the air.
thermal energy- The energy of motion in the
molecules of a substance.
temperature -The average amount of energy of
motion in the molecules of a substance.
thermometer- An instrument used to measure
temperature, consisting of a thin, glass tube with a
bulb on one end that contains a liquid (usually
mercury or alcohol).
Section 4 Water in the Atmosphere p.545-550
relative humidity- The percentage of water vapor
in the air compared to the maximum amount the
air can hold at that temperature.
condensation- The process by which a gas, such
as water vapor, changes to a liquid, such as water.
dew point- The temperature at which
condensation begins.
heat -The energy transferred from a hotter object
to a cooler one.
cumulus- Clouds that form less than 2 kilometers
above the ground and look like fluffy, rounded
piles of cotton.
convection -The transfer of heat by movements of
a fluid.
stratus -Clouds that form in flat layers.
Section 3 Winds p.536-544
wind -The horizontal movement of air from an
area of high pressure to an area of lower pressure.
wind-chill factor- Increased cooling caused by
the wind.
local winds -Winds that blow over short distances.
cirrus -Wispy, feathery clouds made mostly of ice
crystals that form at high levels, above about 6
kilometers.
precipitation- Forms of water such as rain, snow,
sleet, or hail that fall from clouds and reach Earth's
surface.