The Atmosphere: Weather, Air Pressure, Layers, and Air Quality
E N D
Presentation Transcript
Chapter 1 The Atmosphere
What is weather? • Refers to the state of the atmosphere at a specific time and place. • The one thing that you can talk to anybody about! • If you don’t like the weather just wait around it will change!
1.1 The Air Around You • Weather is constantly changing • The atmosphere is the envelope of gases that surrounds the planet
Composition of Air • There are many different types of gasses in the atmosphere
Composition of the atmosphere in percent: • NITROGEN (N2): 78% • OXYGEN (O2): 21% • Other: 1% • CARBON DIOXIDE • WATER VAPOR • METHANE • ARGON • PARTICLES (dust, smoke, salt, chemicals)
Atmosphere Characteristics • Water vapor is the source of all clouds and precipitation. Like carbon dioxide, water vapor absorbs heat given off by Earth. It also absorbs some solar energy.
Ozone is a form of oxygen that combines three oxygen atoms into each molecule (O3). • If ozone did not filter most UV radiation and all of the sun’s UV rays reached the surface of Earth, our planet would be uninhabitable for many living organisms. • It forms when lightening interacts with oxygen in the air.
1.2 Air Pressure • Properties of Air • Because air has MASS, it also has other properties, including DENSITY and PRESSURE. • Density • D = M/V • Pressure- the force pushing on an area or surface. • Air Pressure- The result of the WEIGHT OF A COLUMN OF AIR PUSHING DOWN on an area. • Air pressure changes from day to day. Denser air exerts more pressure than less dense air.
Measuring Air Pressure • Barometer • an instrument that is used to MEASURE AIR PRESSURE. • Two common kinds: 1. MERCURY Barometers-glass tube open at the bottom end and partially filled with mercury • Mercury is pushed higher with more air pressure. • Fig 5, page 12
2. ANEROID Barometers-air tight metal chamber that is sensitive to changes in pressure. • METAL SPRING AND DIAL • Fig 5, page 12
Altitude and Air Pressure • Altitude and properties of Air • Altitude:ELEVATION OR DISTANCE ABOVE SEA LEVEL • Altitude and Air Pressure/Density: • INVERSELY PROPORTIONAL • Increase in ALTITUDE = Decrease in air PRESSURE,LESS air pushing down from above you.
Altitude and Density • The density of air decreases as altitude increases. Air at sea level has more gas molecules in each cubic meter than air at the top of a mountain.
Graphic Organizer Air Pressure measured with decreases as measured in units of Inches of mercury Millibars Barometers Altitude Density decreases include increases Mercury Aneroid
Layers of the atmosphere • There are 4 layers in the atmosphere classified according to temperature changes. • They are the troposphere, stratosphere, mesosphere, and the thermosphere.
Troposphere • This is the layer that is closest to the surface of the earth • It’s elevation ranges from 0 to 12 km • Weather only occurs here
Stratosphere • This layer sits on top of the troposphere • It’s elevation ranges from 12 km to around 50 km • This layer contains the ozone layer, which protects the earth from ultraviolet radiation from the sun.
Mesosphere • This layer is above the stratosphere • It’s elevation ranges from 50 to 80 km • This layer protects the earth from getting hit from asteroids
Thermosphere • This is the highest layer of the atmosphere • It’s height ranges from 80 to 400 km • This is where most small meteorites burn up and is also the location in the atmosphere that the northern lights occur (aurora borealis) • It is divided into the ionosphere (lower layer) and exosphere (upper layer)
Changing Temperatures • The graph shows how temperatures in the atmosphere change with altitude. • Use it to answer the questions that follow.
Changing Temperatures • What two variables are being graphed? In what unit is each measured?
Changing Temperatures Temperature and altitude degrees Celsius and kilometers
Graph Analysis • What is the temperature at the bottom of the stratosphere? • Which layer of the atmosphere has thelowest temperature? • Describe how temperature changes as altitude increases in the troposphere.
1.4 Air Quality • Pollutants- harmful substances in the air, water and soil • They can affect human health and other things
Sources of Pollution Natural sources- forest fires, soil erosion and dust storms. Wind carries particles of mold and pollen. Volcanoes emit clouds of gas, dust, and ash. Human activities- farming, construction, burning of fossil fuels (coal, oil, gas, diesel fuel) Fossil fuels produce a variety of pollutants including carbon monoxide, nitrogen oxides and sulfur oxides
Smog and Acid Rain • Burning of fossil fuels can cause smog and acid rain • London-Type Smog- created when particles in coal smoke combine with water droplets in humid air • Photochemical Smog- brown haze formed by the action of sunlight on pollutants such as hydrocarbons and nitrogen oxides. This is a combination of ozone and other pollutants.
Acid Rain- forms when nitrogen oxides and sulfur oxides combine with water to form nitric acid and sulfuric acid. • Rain, sleet, snow, fog and dry particles can carry these acids to trees and lakes. • It can damage buildings and statues and can make water inhabitable for plants and organism.
Effects of Pollution • Air pollution can cause many different problems. This table shows the health effects of air pollution. Pollen also can cause difficulties for people with allergies.
Improving Air Quality • The Environmental Protection Agency (EPA) monitors air pollutants in the United States. • New model cars and power plants produce fewer pollutants than older models. • Cities are still polluted because there are more power plants and cars with the increase in population. • Reducing pollution can be very expensive.
