Survey
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* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
•The conditions of Earth’s sky at a particular time & place. • ATMOSPHERE- a blanket of gases that surround the earth. •600 miles •Is made up of various atoms & molecules •Nitrogen, Oxygen, Carbon Dioxide, Water Vapor, & other gases/particles. Nitrogen 78% Oxygen 21% Trace gases & other particles (Carbon dioxide, Argon...) 1% Nitrogen •Most abundant gas in the atmosphere. nd •2 Oxygen most abundant gas in the atmosphere •It is essential for plants & animals OZONE •A form of oxygen with 3 oxygen atoms. •It protects us from the sun’s UV rays. Carbon Dioxide •Plants need CO2 to produce food •Burning fuels release CO2. WATER VAPOR • Water in the form of a gas, invisible • Helps clouds form IMPORTANCE OF THE ATMOSPHERE 1. Contains gases that living things need 2. Keeps the surface warm 3. Protects us from UV rays 4. Prevents the surface from being hit by most objects from space. PROPERTIES OF AIR Mass, Density, & Pressure. Mass- the amount of matter in an object •Density- the amount of mass of a substance in a given volume. •Density = Mass/Volume •Pressure- force of an object. AIR PRESSURE • The measure of force of the air pressing down on the earth’s surface. Mass & Air Pressure •In a given volume of air, More mass = More air pressure. •Less mass (less particles) = Less air pressure. Barometer •Instrument that measures air pressure •2 types of barometers: MERCURY BAROMETER A tube with mercury in the center, more air pressure causes the mercury to rise. Less pressure causes the mercury to drop. Aneroid • An air tight metal box. • A change in air pressure causes the needle to move and gives the new air pressure. Two common units used to measure air pressure: 1.Millibars 2. Inches in mercury. Worldwide Air Pressure •29.2 inches is the average •A drop of less than an inch = major storm •A rise of less than an inch = fair weather ALTITUDE •the distance above sea level (elevation). •As you go higher in altitude, air gets thinner (less particles) = less Air Pressure. ASea Level • Air particles are closer together so the air is dense. • More density = More Pressure •Air at sea level (bottom book) 4 Layers of the Atmosphere 1. Troposphere 2. Stratosphere 3. Mesosphere 4. Thermosphere Troposphere • We live in the lowest layer, means “changing” • Earth’s weather occurs here. • As altitude increases, temp. decreases 20C to -60C Stratosphere • 12km to 50km above the earth’s surface. • Contains the ozone layer • Lower part cold -60C, upper part warm 0C because the ozone is absorbing sun’s energy. Mesosphere •Above stratosphere, colder, middle layer (0- -90C) •Protects earth’s surface from being hit by most meteoroids. Thermosphere • Top layer of atmosphere, air so spread out • Very hot (1,800C) but doesn’t read because particles are so spread out. • Breaks into 2 layers: ionosphere, & exosphere IONOSPHERE • Lower part of Thermosphere 80-400 KM • Contains charged particles (ions) that light up the night sky- Aurora Borealis • -90C, EXOSPHERE •Top layer of Thermosphere, 400+km •No limit, satellites • Harmful substances in air, water, or soil. 1. Natural- forest fires, soil erosion, dust storms, volcanoes. 2. Human Activities- burning of fossil fuels (cars, factories, power plants) •When fossil fuels burn, they release particles into the air. Some of these pollutants are: carbon monoxide, carbon dioxide, nitrogen oxide, & sulfur oxide. • The burning of fossil fuels causes smog & acid rain. • London-Type Smog- using coal caused particles of coal smoke to combine with water vapor producing a dark smog in England. London-Type Smog • Photochemical Smog- a brown haze in cities, chemicals from burned fossil fuels mix with sunlight, ozone, & other pollutants. Photochemical Smog ACID RAIN •rain that is more acidic than usual, formed from the burning of coal which produces sulfur oxides which mix with water vapor in the air. • In the US, the government has passed laws to reduce pollution. • Environmental Protection Agency (EPA) monitors air quality.