Transcript File

Chapter 12 S1-3 Review
Ch12 S1: Essential Questions
1. What is the composition of Earth’s
atmosphere?
2. How is the atmosphere important to living
things?
3. What causes smog and acid rain?
• Weather is the condition of Earth’s
atmosphere at a particular time and place.
• Earth’s atmosphere is a thin envelope of
gases that surrounds the planet and
protects it.
• It is a thin layer of air forming a protective
covering around the planet. (from Glencoe
book)
What is the atmosphere made of?
• It is made of gases, solids and liquids
– Solids include dust, salt, and pollen
• It is 78% nitrogen, 21% oxygen, and 1%
other materials
• It has 4 main layers
Nitrogen
Oxygen
Other
Ozone
• “supercharged oxygen”
• Formed from oxygen with three oxygen
atoms in each molecule instead of the
usual two
• The ozone layer helps protect Earth from
ultraviolet radiation given off by the Sun
Water Vapor
• Water in the form of a gas
• It is invisible (steam is tiny droplets of
water and is NOT water vapor)
• Very important in weather
• Clouds form when water vapor condenses
on something (usually dust) to form tiny
droplets of water in the air
What does the atmosphere do for us?
• It traps oxygen close to Earth for us to breathe.
• It helps keep the perfect temperature on Earth
for plants and us to live. It traps energy from the
Sun. Without it there would be no liquid water.
• It protects the planet from harmful ultraviolet
radiation from the Sun.
• It protects us from space objects striking Earth
(such as meteoroids – space rocks)
• Because the atmosphere is constantly changing,
the air can be considered a renewable resource
Sources of Pollution
• Natural processes can add particles to the
atmosphere
– Forest fires, soil erosion, dust storms all add
smoke and dust to the air
– Wind carries molds and pollens
– Erupting volcanoes spew out dust, ash, and
poisonous gases
• Human events that add pollution to the air
– Burning fossil fuels (vehicles, factories)
Acid Rain
• Rain that contains more acid than normal
• Caused when water vapor mixes with
harmful chemicals in the air. These
chemicals were released by burning fossil
fuels
• Can be strong enough to damage surfaces
of buildings and statues
• Harmful to lakes and ponds
Ch 12 S2: Essential Questions
1. What are some of the properties of air?
2. What instruments are used to measure air
pressure?
3. How does increasing altitude affect air pressure
and density
Pressure
The force pushing on an area is pressure.
Air pressure is the result of the weight of a column
of air pushing down on an area.
The column of air that extends upward through the
entire atmosphere.
Measuring Air Pressure
A barometer is an instrument that is used to
measure air pressure. Two kinds of barometers
are mercury barometers and aneroid barometers.
Barometers
Mercury
Aneroid
Altitude and the Properties of Air
Air pressure decreases as altitude increases. As air
pressure decreases, so does density.
At sea level air has all the weight of the whole
atmosphere pressing on it (=more pressure). The
air at the top of the mountain has less weight
pressing on it (= less pressure).
Altitude Affects Density
The air contains 21 percent oxygen, whether you are at sea
level or on top of a mountain. So when you are at a higher
altitude there is less oxygen per cubic meter. Same
amount in the air just not compacted together. The oxygen
molecules are more spread out. So you will give out of breath
easily at higher altitudes due to not getting as much oxygen in
each breath.
Ch12 S3: Essential Questions
1.What are the four main
layers of the atmosphere?
2.What are the
characteristics of each
layer?
Earth’s atmosphere is divided
into four main layers based upon
changes in temperature.
Troposphere
• Lowest layer of the atmosphere (closest to Earth)
• You live here
• Tropo means turning or changing (there is more
change in this layer than any other)
• Weather occurs here
• Shallowest layer (thinnest)
• Contains almost all the mass of the atmosphere
• It is 16 km thick at equator and less than 9 km
thick at poles – it is oval shaped
• As altitude increases, temperature decreases
• At the top, temp is about -60 ̊C. Water here
forms clouds of ice
Stratosphere
• Second layer of the atmosphere
• Reaches from troposphere to about 50 km above
surface of Earth
• Strato means layer or spread out
• Ozone layer is here (remember it protects living
things from ultraviolet radiation from Sun)
• Jets often fly here because it is calm
• As altitude increases, temperature increases
(because ozone layer absorbs heat)
Mesosphere
• Third layer
• Meso means middle
• Reaches from 50 km to 80 km above Earth’s
surface
• Protects Earth’s surface from being hit by
meteoroids (chunks of stone and metal from
space – but some still get through)
• A shooting star is a trail of hot, glowing gases a
meteoroid leaves behind in the mesosphere
• Coldest layer - Temperatures reach – 90 ̊C at the
top of the mesosphere
• As altitude increases, temperature decreases
Thermosphere
• Outermost layer of our atmosphere
• Reaches from 80 km above Earth’s surface into
outer space. There is no definite upper limit
• Thermo means heat
• Thickest layer
• Hottest layer, temperatures reach up to 1,800 ̊C,
but you would not feel warm here
• As altitude increases, temperature increases
• Has two other layers
Ionosphere
• Lower layer of the Thermosphere
• Reaches from about 80 km to 400 km above
Earth’s surface
• Energy from the sun causes gas molecules here
to become electrically charged particles
• Radio waves bounce off ions back to Earth
(makes signals travel much farther at night)
• Auroras happen near the poles because of the
ionosphere – these are brilliant streaks of light in
night skies
Exosphere
• Exo means outer
• Is the outer portion of the thermosphere
• Reaches from about 400 km outward for
thousands of kilometers
• Space shuttles and satellites orbit Earth
here
Review Questions
Review Quiz
1. The most abundant gas in the
atmosphere is
a.
b.
c.
d.
Ozone
Water vapor
Oxygen
Nitrogen
Quiz continued
2. ___________ is the condition of Earth’s
atmosphere at a particular time and
place.
a.
b.
c.
d.
Climate
Temperature
Weather
Ozone
Quiz continued
3. True or False: Earth’s atmosphere
makes conditions on Earth suitable for
living things.
4. Smog and acid rain can be caused from
burning
a.
b.
c.
d.
Coal
Petroleum oil
Natural gas
All of the above
Quiz
1. Air pressure is typically
measured with a ___________.
2. The force pushing on an area
or surface is known as
___________.
3. As density of air decreases, its
pressure ____________.
4. Air pressure is often
measured in _____________.
•
•
•
•
•
•
•
•
Word Bank
increases
decreases
air pressure
altitude
millibars
barometer
thermometer
inches
Review Quiz
1. List the four main layers of the
atmosphere in order from the surface of
Earth.
2. What is the hottest layer of the
atmosphere?
a. Troposphere
c. Mesosphere
b. Stratosphere
d. Thermosphere
Quiz (continued)
3. What layer do you live in?
a. Troposphere
c. Mesosphere
b. Stratosphere
d. Thermosphere
4. What layer contains the ozone layer?
a. Troposphere
c. Mesosphere
b. Stratosphere
d. Thermosphere