Atmosphere 15.1

1. CH. 15-1CH. 15-1
EARTH’SEARTH’S
ATMOSPHEREATMOSPHERE

2. ImportanceImportance
Atmosphere – a thin layer Atmosphere – a thin layer
of air that forms a of air that forms a
protective covering around protective covering around
Earth.Earth.
It keeps Earth’s It keeps Earth’s
temperature in a range that temperature in a range that
can support life.can support life.

3. ImportanceImportance
It also protects life-forms It also protects life-forms
from some of the Sun’s from some of the Sun’s
harmful rays.harmful rays.

4. Makeup of Atmos.Makeup of Atmos.
It is a mixture of solids, It is a mixture of solids,
liquids, & gases that liquids, & gases that
surround the planet.surround the planet.

5. Gases in the Atmos.Gases in the Atmos.
Nitrogen = 78%Nitrogen = 78%
Oxygen = 21%Oxygen = 21%
COCO
22 = 0.03%, but could be = 0.03%, but could be
increasing due to burning increasing due to burning
fossil fuels for energy.fossil fuels for energy.

6. Layers of the Atmos.Layers of the Atmos.
5 layers make up Earth’s 5 layers make up Earth’s
atmosphere:atmosphere:
Troposphere & Troposphere &
StratosphereStratosphere
Mesosphere, Mesosphere,
thermosphere, & thermosphere, &
exosphereexosphere

9. Lower LayersLower Layers
Troposphere - the lowest Troposphere - the lowest
layer of Earth’s layer of Earth’s
atmosphere.atmosphere.
Extends up about 11 mi or Extends up about 11 mi or
10 km10 km
Contains clouds, rain, & Contains clouds, rain, &
snow.snow.

10. Lower LayersLower Layers
Stratosphere is directly Stratosphere is directly
above troposphereabove troposphere
Extends from 10 km – 50 Extends from 10 km – 50
km abut Earth’s surfacekm abut Earth’s surface
Contains a gas called Contains a gas called
ozone (Oozone (O
33))

11. Upper LayersUpper Layers
Mesosphere – extends Mesosphere – extends
from top of stratosphere to from top of stratosphere to
about 85 km above Earth about 85 km above Earth
Shooting stars (meteors) Shooting stars (meteors)
occur hereoccur here

12. Upper LayersUpper Layers
Thermosphere – the Thermosphere – the
thickest layer of the thickest layer of the
atmosphere (between 85 atmosphere (between 85
km & 500 km) above Earth. km & 500 km) above Earth.
Very hot! Temps. can reach Very hot! Temps. can reach
2000 degrees!2000 degrees!

13. Upper LayersUpper Layers
IonosphereIonosphere is a layer of is a layer of
electrically charged electrically charged
particles found within the particles found within the
thermosphere.thermosphere.
Absorbs AM radio waves Absorbs AM radio waves
during day, reflects them at during day, reflects them at
night.night.

14. Upper LayersUpper Layers
ExosphereExosphere – last (highest) – last (highest)
layer of the atmospherelayer of the atmosphere
Extends more than 500 km Extends more than 500 km
above Earth (very cold)above Earth (very cold)
Marks the transition from Marks the transition from
Earth’s atmosphere to Earth’s atmosphere to
outer space.outer space.

16. Atmospheric PressureAtmospheric Pressure
Earth’s gravity pulls Earth’s gravity pulls
atmospheric gases toward atmospheric gases toward
its surface, & the weight of its surface, & the weight of
the gases presses down on the gases presses down on
the air below.the air below.
Air pressure decreases Air pressure decreases
with height.with height.

17. Ozone LayerOzone Layer
Lies within the Lies within the
stratosphere.stratosphere.
Blocks Sun’s harmful Blocks Sun’s harmful
energy (UV radiation) energy (UV radiation)
which is very important to which is very important to
us.us.
UV = Ultraviolet UV = Ultraviolet

19. CFCsCFCs
CFCs - chlorofluorocarbonsCFCs - chlorofluorocarbons
They destroy ozone by the They destroy ozone by the
chlorine combining with one chlorine combining with one
of the oxygen atoms in ozone.of the oxygen atoms in ozone.
Allows more UV light to reach Allows more UV light to reach
the Earth. the Earth.

20. CFCsCFCs
CFCs are found in Freon CFCs are found in Freon
(used to cool refrigerators, air (used to cool refrigerators, air
conditioners) & aerosol spray conditioners) & aerosol spray
cans (hair spray & spray cans (hair spray & spray
paints) paints)
One atom of chlorine can One atom of chlorine can
destroy 100,000 ozone destroy 100,000 ozone
molecules!!molecules!!