The Atmosphere

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The Atmosphere:

The Atmosphere The ocean of air all around us

Weather:

Weather The condition of the Earth’s atmosphere at a particular time and place

Atmosphere:

Atmosphere The layer of gases that surrounds the planet

Earth’s Atmosphere:

Earth’s Atmosphere Makes conditions on Earth suitable for living things Holds heat around our planet, while protecting us from harmful radiation from the sun Protects us from small meteoroids which burn up as they pass through the atmosphere

Composition of the Atmosphere:

Composition of the Atmosphere 78% nitrogen 21% oxygen 1% other gases; such as carbon dioxide, water vapor, argon, neon, helium, methane, krypton, hydrogen

Nitrogen:

Nitrogen Essential to living things A component of amino acids and proteins Is converted by bacteria in soil into a form that plants can use Plants use nitrogen in photosynthesis to make sugars from sunlight

Oxygen:

Oxygen Free oxygen is made of two atoms of oxygen Essential to life Produced by plants during photosynthesis Necessary for fire to occur Causes rust to occur on steel or iron in a process called oxidation

Ozone:

Ozone A form of oxygen that has three oxygen atoms in each molecule Is formed when lightening interacts with oxygen in the air Is also formed by sunlight reacting with electrically charged molecules in the atmosphere

Carbon Dioxide:

Carbon Dioxide Each molecule of carbon dioxide has one atom of carbon and two atoms of oxygen Plants use carbon dioxide to make sugars during photosynthesis Animals give off carbon dioxide as a waste product Also produced during the burning of fossil fuels such as gasoline

Water Vapor:

Water Vapor The form of water as a gas Varies greatly from place to place, and time to time Plays an important role in Earth’s weather Clouds form when water vapor condenses out of the air to form tiny droplets of liquid water or crystals of ice which fall as rain or ice

Air:

Air Also contains particles of dust, pollen, smoke, salt, and other chemicals

Air Quality:

Air Quality The measurement of how pure the air is Is affected by the amount of pollution, pollen, mold, dust, soot and other particles in the air

Pollution:

Pollution Harmful substance in the air, water or soil Has known harmful effects on human health as well as other living things Most pollution is the result of burning fossil fuels such as coal, oil, gasoline, and diesel

Natural Sources:

Natural Sources Ocean waves splashing salt water which evaporates and tiny particles of salt enter air and soil Forest fires, soil erosion and dust storms Erupting volcanoes spew out clouds of ash and poisonous gases Pollen from flowering plants causes allergic reactions

Artificial Sources:

Artificial Sources Burning fossil fuel, wood and coal Factories, cars, aerosols, trash, improper disposal of chemicals, paint, oil, etc.

Coastal Pollution:

Coastal Pollution

London-Type Smog:

London-Type Smog Forms when particles in coal smoke combine with water droplets in the air

Photochemical Smog:

Photochemical Smog Is formed when sunlight reacts with the pollution in the air Causes a brown haze that is often around cities, especially during the summer Can cause breathing problems in some people, harms plants, damages rubber, paint and some plastics

Temperature Inversion:

Temperature Inversion When a layer of warm air prevents the rising air from escaping, the polluted air is trapped and held close to Earth’s surface

Acid Rain:

Acid Rain Is the result of nitrogen oxides and sulfur oxides which combine with water in the air to form nitric acid and sulfuric acid Damages or kills plants, forests, lakes, wildlife and the surfaces of buildings statues and painted surfaces

Improving Air Quality:

Improving Air Quality Federal and state governments have passed a number of laws and regulations to reduce air pollution For example; filters on smokestacks, more fuel efficient cars which release less emissions

Air Pressure:

Air Pressure The result of the weight of a column of air pushing down on an area Air pressure averages about 14.7 pound per square inch (that is about the weight of an elephant sitting on your body, or a school bus sitting on your desk

Density:

Density The amount of mass in a given volume of a substance, or the number of molecules in a space Density equals mass divided by volume

Pressure:

Pressure The force pushing on an area or surface A denser substance has more mass per unit volume and therefore can exert more pressure The denser air is the more air pressure it exerts

Barometer:

Barometer A tool used to measure air pressure Pressure is measured in units called millibars

Mercury barometer:

Mercury barometer Consists of a glass tube open at the bottom end and partially filled with mercury

Aneroid barometer:

Aneroid barometer Has an airtight metal chamber which is sensitive to pressure

Altitude:

Altitude Also called elevation, is the distance above average level of the surface of the oceans Air pressure decreases as altitude increases As air pressure decreases, so does density

Layers of the Atmosphere:

Layers of the Atmosphere There are four main layers to the atmosphere Classified according to changes in temperature They are; troposphere, stratosphere, mesosphere and the thermosphere

Troposphere:

Troposphere The inner or lowest layer of the atmosphere Weather occurs in this layer Its depth varies from more than 16 km above the equator to less than 9 km above the North and South Poles As altitude increases in the troposphere, temperature decreases

Stratosphere:

Stratosphere Extends from the top of the troposphere to 50 km above Earth’s surface Temperatures in the lower stratosphere are cold, about -60 ° C The upper stratosphere is warmer because of the ozone layer which absorbs energy from the sun which is converted to heat t

Mesosphere:

Mesosphere The middle layer of the atmosphere Its also the coldest layer with temperatures below -90 ° C It begins at about 50 km above the Earth to about 80 km The mesosphere protects us from meteoroids most of which burn up in this layer

Thermosphere:

Thermosphere Near the top of the atmosphere, about 80 km above the Earth The air is very thin, and it is very hot, up to 1,800 ° C It is divided into two layers, the ionosphere and the exosphere

Ionosphere:

Ionosphere The lower layer of the thermosphere Contains electrically charged particles which cause radio waves to bounce off of it When the solar wind strikes these electrically charged particles it causes the aurora borealis-the Northern Lights

Exosphere:

Exosphere Extends out to about 550 km It is where satellites orbit the Earth Satellites are used for television and telephone signals, as well as for images of weather systems

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