Atmosphere in Motion Chapter 12 By Amy Johnson

Atmosphere gases surrounding the Earth gases surrounding the Earth –necessary for supporting life –protects against harmful UV and X-ray radiation –absorbs and distributes warmth

Galileo Galilei proved air must have weight and contain matter proved air must have weight and contain matter –Weighed flask, injected air, and reweighed to find flask with injected air weighed more Air stores and releases heat, holds moisture, and can exert pressure Air stores and releases heat, holds moisture, and can exert pressure

Composition of Atmosphere subject to the pull of gravity subject to the pull of gravity –exerts pressure in all directions, therefore cannot be felt –weight is equal to water over 10 m deep mixture of gases, liquid water, and microscopic particles of solids and other liquids mixture of gases, liquid water, and microscopic particles of solids and other liquids

Gases of the Atmosphere Nitrogen – most abundant (78%) Nitrogen – most abundant (78%) Oxygen – necessary for human life (21%) Oxygen – necessary for human life (21%) Variety of other gases in trace amounts Variety of other gases in trace amounts –water vapor is critical to weather (up to 4%) »Responsible for clouds and precipitation –carbon dioxide allows plants to make food (.03%) »Absorbs heat and emits it back to warm Earth

Aerosols in the Atmosphere solids, such as dust, salt, and pollens and tiny droplets of acid solids, such as dust, salt, and pollens and tiny droplets of acid –dust comes from volcanoes and wind blowing across the soil –salt results from wind blowing over the ocean –pollen is released by plants –burning coal in power plants also creates aerosols

Layers of the Atmosphere Layers of the Atmosphere Lower Layers Lower Layers –Troposphere –Stratosphere Upper Layers –Mesosphere »Ionosphere –Thermosphere –Exosphere based on temperature changes that occur with altitude

Troposphere closest to the Earth (about 10 km) closest to the Earth (about 10 km) contains about ¾ of Earth’s entire atmosphere including clouds and weather contains about ¾ of Earth’s entire atmosphere including clouds and weather about 50% of Sun’s energy passes through about 50% of Sun’s energy passes through Earth’s surface heats by conduction Earth’s surface heats by conduction –the farther from the surface you get, the cooler it becomes

Stratosphere above troposphere (10 km – 50 km) above troposphere (10 km – 50 km) contains most of the ozone contains most of the ozone –Absorbs ultraviolet radiation to warm area »As you go up, you get warmer –without ozone, the UV radiation would reach Earth and cause health problems

Mesosphere Extends 50km – 85km above surface Extends 50km – 85km above surface Contains very little ozone so temperature drops to the lowest in atmosphere Contains very little ozone so temperature drops to the lowest in atmosphere

Ionosphere part of mesosphere and thermosphere part of mesosphere and thermosphere due to intense interaction with the sun’s radiation due to intense interaction with the sun’s radiation reflects AM radio waves allowing long- distance communications possible reflects AM radio waves allowing long- distance communications possible –static results when interaction between this layer and radiation is too active

Thermosphere reaches 85km – 500km reaches 85km – 500km temperatures increase rapidly temperatures increase rapidly filters out harmful X-rays and gamma rays from the Sun filters out harmful X-rays and gamma rays from the Sun

Exosphere outermost layer outermost layer extends outward to where space begins extends outward to where space begins –no clear boundary to space GREENHOUSE EFFECT

Earth’s Water 70% of Earth’s surface is water 70% of Earth’s surface is water Stored throughout the land-ocean- atmosphere system in three different states Stored throughout the land-ocean- atmosphere system in three different states –Solid – snow, ice, glaciers –Liquid – oceans, lakes, rivers –Gas – water vapor Water Cycle Water Cycle Water Cycle Water Cycle