Transcript The Atmosphere The Atmosphere     The Air Around You Air Quality Air Pressure Layers of the Atmosphere.

The Atmosphere
The Atmosphere
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The Air Around You
Air Quality
Air Pressure
Layers of the Atmosphere
The Air Around You - Vocabulary
 Weather – The condition of Earth’s
atmosphere at a particular time and place.
 Atmosphere – The layer of gases that
surrounds Earth.
 Ozone – A form of oxygen that has three
oxygen atoms in each molecule instead of
the usual two.
 Water vapor – Water in the form of a gas.
The Air Around You – Main Ideas
 Earth’s atmosphere makes conditions on
Earth suitable for living things.
 Earth’s atmosphere is made up of nitrogen,
oxygen, carbon dioxide, water vapor, and
many other gases, as well as particles of
liquids and solids.
The Air Around You – Guiding
Questions
 Describe two ways in which the atmosphere
is important to life on Earth.
 What are the four most common gases in
dry air?
 Why are the amounts of gases in the
atmosphere usually shown as percentages
of dry air?
Air Quality - Vocabulary
 Pollutants – Harmful substances in the air,
water, or soil.
 Photochemical smog – A brownish haze that
is a mixture of ozone and other chemicals,
formed when nitrogen oxides, hydrocarbons,
and other pollutants react with each other in
the presence of sunlight.
 Acid rain – Rain that contains more acid
than normal.
Air Quality – Main Ideas
 Most air pollution is the result of burning fossil
fuels such as coal, oil, gasoline, and diesel fuel.
 Nitrogen oxides, hydrocarbons, and other air
pollutants react with one another in the presence
of sunlight to form a mix of ozone and other
chemicals called photochemical smog
 Acid rain forms when nitrogen oxides and sulfur
oxides combine with water in the air to form nitric
acid.
Air Quality – Guiding Questions
 How is most air pollution produced?
 Name two natural and two artificial sources
of particles in the atmosphere.
 How is photochemical smog formed? What
kinds of harm does it cause?
 What substances combine to form acid rain?
Air Pressure - Vocabulary
 Density – The amount of mass of a
substance to a given volume.
 Pressure – The force pushing on an area or
surface.
 Air pressure – A force that is the result of the
weight of a column of air pushing down on
an area.
 Barometer – An instrument used to measure
changes in air pressure.
Air Pressure - Vocabulary
 Mercury barometer – An instrument that measures
changes in air pressure, consisting of a glass tube
partially filled with mercury, with its open end
resting in a dish of mercury. Air pressure pushing
on the mercury in the dish forces the mercury in
the tube higher.
 Aneroid barometer – An instrument that measures
changes in air pressure without using a liquid.
Changes in the shape of an airtight metal box
cause a needle on the barometer dial to move.
 Altitude - Elevation above sea level.
Air Pressure
 Properties of air include mass, density, and
air pressure.
 Air pressure is the result of the weight of a
column of air pushing down on an area.
 Air pressure is measured with mercury
barometers and aneroid barometers.
 Air pressure decreases as altitude
increases. As air pressure decreases, so
does density.
Air Pressure – Guiding Questions
 How does increasing the density of a gas
affect its pressure?
 Describe how a mercury barometer
measures air pressure.
 Why is the air at the top of a mountain hard
to breathe?
Layers of the Atmosphere Vocabulary
 Troposphere – The lowest layer of Earth’s
atmosphere, where weather occurs.
 Stratosphere – The second-lowest layer of Earth’s
atmosphere; the ozone layer is located in the
upper stratosphere.
 Mesosphere – The middle layer of Earth’s
atmosphere; the layer in which most meteoroids
burn up.
 Thermosphere – The outermost layer of Earth’s
atmosphere.
Layers of the Atmosphere Vocabulary
 Ionosphere – The lower part of the thermosphere,
where electrically charged particles called ions are
found.
 Aurora borealis – A colorful, glowing display in the
sky caused when particles from the sun strike
oxygen and nitrogen atoms in the ionosphere; also
called the Northern Lights.
 Exosphere – The outer layer of the thermosphere,
extending outward into space.
Layers of the Atmosphere
 The thermosphere is
composed of the
ionosphere (80-550
km) and the exosphere
(above 550 km)
 Mesosphere (50-80
km)
 Stratosphere (12-50
km)
 Troposphere (0-12 km)
Layers of the Atmosphere – Main
Ideas
 The four mail layers of the atmosphere are
classified according to changes in
temperature. These layers are the
troposphere, the stratosphere, the
mesosphere, and the thermosphere.
 Rain, snow, storms, and most clouds occur
in the troposphere.
 Ozone in the stratosphere absorbs energy
from the sun.
Layers of the Atmosphere – Main
Ideas
 Most meteoroids burn up in the
mesosphere, producing meteor trails.
 The aurora borealis occurs in the
ionosphere.
 Communications satellites orbit Earth in the
exosphere.
Layers of the Atmosphere – Guiding
Questions
 Describe one characteristic of each of the
four main layers of the atmosphere.
 What is a shooting start? In which layer of
the atmosphere would you see it?
 What is the aurora borealis? In which layer
of the atmosphere does it occur?