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Earth’s Atmosphere. State Standards for 5 th Grade Earth Science 4.E. and Visual Art 5.2 . Atmosphere. Atmosphere (Definition) – Layer of air that surrounds our planet. GREEK for “ball of fire” http://brainpop.com/science/seeall.weml.
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Earth’s Atmosphere State Standards for 5th Grade Earth Science 4.E. and Visual Art 5.2
Atmosphere • Atmosphere (Definition) – Layer of air that surrounds our planet. • GREEK for “ball of fire” http://brainpop.com/science/seeall.weml • Atmosphere (Definition) – Layer of air that surrounds our planet. • GREEK for “ball of fire” http://brainpop.com/science/seeall.weml
Atmosphere • Looks like a very thin blanket surrounding our planet • Needed by all living things to carry out life processes • Put the atmosphere in a big box & it would weigh about 6,000 trillion tons = 33 billion large railway engines
Atmosphere • Mixture of various gases • Almost 4/5 Nitrogen (enriches soil/helps plants grow) • 1/5 oxygen (animals/humans breath it) • Combined = 99% of atmosphere • Also contains particles spewed fr/volcanoes, salt fr/sea spray, dust fr/meteors, sand fr/sand storms, soot fr/forest fires, rubber fr/vaporized car tires, pollen grains fr/plants, chemicals fr/fertilizers/pesticides, dust, & other human waste (pollution)
Atmosphere • Other gases needed: • Ozone shields us fr/ultraviolet radiation • Carbon Dioxide for plants and it also absorbs heat energy from sun and Earth’s surface, keeping planet warm.
Formation of Atmosphere • Formed millions of years ago – gases from erupting volcanoes collecting around planet. • Bacteria/other living things used the gases and released NEW gases (life processes) • Over time, gas mixture changed to look like what it is today
Air Pressure • Air takes up space and has weight • Particles of air pressing down on Earth’s surface causes air pressure (14.7 lbs per sq in) • Changes as you go higher in atmosphere • Helps drive Earth’s winds • The sun heats air near land, ocean, mtns. Differently. Warm, rising air creates high-pressure areas, while sinking, cooling air causes low-pressure. • Air constantly moves fr/warm areas of high-pressure to cool areas of low-pressure. • The greater the temp difference fr/one area to another, the HARDER the wind blows!
Air Pressure • See page B7 (diagram and caption) • Surface: close together • As you go higher in atmosphere, they are further apart • Is air pressure greater or less as you go higher?
Atmosphere Layers • There are 4 MAJOR Layers – BUT they lack sharp boundaries (flexible) • Each layer has its own range of pressure and temp that makes it distinctive fr/the others • They eventually fade into outer space where there is no air at all
Atmosphere Layers • Troposphere: closest to the Earth and contains 99% of our planet’s air • Where we live • Breathe its air • Provides us weather • Lower layer contains large amounts of water vapor • Air moves over the land as wind • Air temperature decreases as you go higher • From the U.S., it goes up about 8 miles
Atmosphere Layers • Stratosphere • Contains most of atmosphere’s ozone • Protects living things from sun’s harmful rays • Temperatures increase with height • Some airplanes fly here • Starts where troposphere ends & continues for 30 miles • Lower regions extremely cold/swept by strong winds • Top portion has jet streams (300mph) w/temp gradually rising (caused by ozone)
Atmosphere Layers • Mesosphere • Coldest layer of the atmosphere • Starts at 30 degrees F & decreases to -130 degrees F (Air temperature decreases with height) • 20 miles deep • Air is ultra-thin • Sky appears black • Sound cannot travel through it
Atmosphere Layers • Thermosphere • Hot, outermost layer of atmosphere (Borderline of space) • Temperature quickly increases with height • Higher area can reach 1,093 degrees C • Gas molecules can travel 2,000 miles before bumping into another molecule • Uppermost region btwn 260-900 miles above Earth
What is atmosphere? Where is it located? How was it formed? What is it like now? What helps keep our planet warm? What is relationship between air pressure and the atmosphere? How does it change as you move from Earth to outer space? Review
Review • What are the four Atmosphere layers? • Describe the properties of each.
Why is the Sky Blue? • Sunlight shines through air, moving among gas molecules & fine dust particles. Rays bounce around them and scatter the particles. Because the white light of the sun is made of colors we see in a rainbow, each color travels through air as waves. Red=longest, orange=next longest, etc. Violet & blue=shortest (also closest to the size of gas molecules in the air. Hence, they are scattered the most and reach our eyes as BLUE. • Darkening occurs as air thins& fewer molecules are available to scatter light. At top of atmosphere, there are so few gas molecules that there is no scattering.
Instructions for assignment • Draw a picture of the Earth’s atmospheric layers • On the same sheet of paper, next to or within the layer, describe the characteristics of that layer. • Begin assignment in class