23.1 Characteristics of the Atmosphere

Composition of the Atmosphere

• What is the most abundant gas in the atmosphere???

• NITROGEN

• Another gas that is not shown in the graph is water vapor.

• Water vapor fluctuates due to evaporation, transpiration, and condensation.

Journal:

What do you know about ozone?

Ozone in the Atmosphere

O3, Ozone

• Absorbs harmful ultraviolet radiation

• Ultraviolet Radiation is harmful because it causes damage to our cells (UV A and UV B)

Destruction of the Ozone Layer

• Compounds called Chlorofluorocarbons, CFCs, and nitrogen oxide break down ozone.

Journal:

• What are the possible effects of continued breakdown of the ozone layer? (support your response by explaining why you think this might happen)

Oxygen in the Atmosphere

Nitrogen in the Atmosphere

Atmospheric Pressure• Pressure air = Force air / surface area• Gravity pulls the gasses of the atmosphere

toward the Earth’s surface

Measuring Atmospheric Pressure• Barometer: measures atmospheric pressure

– Mercurial Barometer: atmospheric pressure presses down on liquid mercury raising the mercury in a tube.

Measuring Atmospheric Pressure• Barometer: measures atmospheric pressure

– Aneroid Barometer: atmospheric pressure causes a vacuum sealedchamber to collapse under atmospheric pressure. Changes are indicated by a pointer

Layers of the atmosphere

Does temperature change in the layers of the atmosphere?

How does temperature change with each layer?

Layers of the Atmosphere

• Layers of the atmosphere are identified based on temperature differences

Layers of the Atmosphere

• Troposphere: Closest to earth’s surface– Where all weather

changes occur– Temp. decreases with

increasing altitude

Layers of the Atmosphere

• Stratosphere: Extends from the Troposphere to 50 km– Temperature increases

with increasing altitude– The ozone layer is found

here– Stratopause: upper

boundary with the highest temperature

Layers of the Atmosphere

• Mesosphere: From 50 km to 80 km above earth’s surface– Temperature decreases

with increasing altitude– Coldest layer of the

atmosphere

Layers of the Atmosphere

• Thermosphere: From 80 km – Temperature increases

with increasing altitude– Nitrogen and oxygen absorb

solar energy– Ionosphere: 80km – 550km,

reflect radio waves– Exosphere: above 550 km,

blends into space

Air Pollution

• Air Pollutants: substances in the air that are harmful to plants, animals, water systems, ozone layer– Examples: Sulfur dioxide, carbon monoxide, lead,

hydrocarbons

• What is the source of air pollutants?– Burning of fossil fuels

The Effects of Air Pollution• Acid Precipitation

The Effects of Air Pollution• Temperature Inversions

Layers of the atmosphere activity.