Earth Science Chapter 7 Atmosphere https://www.youtube.com/watch?v=TGBQazOQfoE https://www.youtube.com/watch?v=I6jIMkPwahQ The Air Around You Earth's atmosphere is the envelope of gases that surrounds the planet. Earth's atmosphere is the envelope of gases that surrounds the planet. made up of nitrogen, oxygen, carbon dioxide, water vapor, and many other gases, as well as particles of liquids and solids made up of nitrogen, oxygen, carbon dioxide, water vapor, and many other gases, as well as particles of liquids and solids Weather is the condition of Earth's atmosphere Weather is the condition of Earth's atmosphere Importance of Atmosphere 1. Contains gasses that living things need 2. Keeps surface of earth warm 3. Protects from dangerous ultra violet radiation 4. Allows water to exist as a liquid 5. Prevents the surface from being hit by most objects from outer space Air Pressure Air pressure is the result of the weight of a column of air pushing down on an area lbs/inch lbs/inch millibars millibars hPa (hecto Pascals) hPa (hecto Pascals) inches of Hg inches of Hg 1 in x 1 in square column of air weighs 14.7 lbs at sea level Barometer is an instrument that is used to measure air pressure. Mercury barometer consists of a glass tube open at the bottom end and partially filled with mercury At sea level, the Mercury column is 76cm high Measuring Air Pressure Aneroid barometer has an airtight metal chamber, no liquid Air Pressure & Altitude Elevation the distance above sea level. As altitude increases Air pressure decreases As air pressure decreases, so does density. Layers of the Atmosphere Scientists divide Earth's atmosphere into four main layers classified according to changes in temperature. Troposphere tropo = changing sea level to 12 km (9 km at poles and 16km at equator) sea level to 12 km (9 km at poles and 16km at equator) All weather occurs here All weather occurs here Has almost all mass of atmosphere Has almost all mass of atmosphere Temp. decreases with altitude Temp. decreases with altitude Stratosphere from 12 to 50 km from 12 to 50 km Ozone layer, protects from UV, jets fly here Ozone layer, protects from UV, jets fly here Temp. increases with altitude (middle part of stratosphere has ozone layer which absorbs energy from the sun and converts it to heat) Temp. increases with altitude (middle part of stratosphere has ozone layer which absorbs energy from the sun and converts it to heat) Mesosphere - Meso = middle Meso = middle from 50 to 80 km from 50 to 80 km Protects earth from meteoroids; burn with friction Protects earth from meteoroids; burn with friction Temperature decreases with altitude (fewer ozone molecules) Temperature decreases with altitude (fewer ozone molecules) Thermosphere Thermo = heat.001 percent as dense as the air at sea level 80 km to space Temp up to 1800 C even though air is very thin, because sunlight strikes the thermosphere first, N 2 and O 2 molecules convert this energy into heat Thermometer will show 0C because there are not enough molecules to touch collide with a thermometer and warm it. made up of 2 layers Ionosphere 80 km to 400 km Gas particles electrically charged Radio waves reflect back to Earth from here Aurora borealis occur here Exosphere above 400 km Satellites orbit here Layers of the Atmosphere The term pause refers to between layers. Energy in Earth's Atmosphere Energy travels to Earth as electromagnetic radiation from the Sun. EM Waves are classified according to wavelength (distance between waves) 1. Visible Light VIBGYOR Red and Orange longest wavelengths Blue and Violet shortest wavelength 2. Infra Red invisible, longer than red, felt as heat 3. Ultraviolet invisible, shorter than violet, cause sunburns, skin cancer, eye damage EMR travels through the atmosphere & heats the surface of the Earth EMR travels through the atmosphere & heats the surface of the Earth Some solar radiation is absorbed Ozone (UV Rays), water vapor, clouds, dust, CO 2 absorb energy Some solar radiation is absorbed Ozone (UV Rays), water vapor, clouds, dust, CO 2 absorb energy Reflected clouds, dust particles, gases (scattering) Reflected clouds, dust particles, gases (scattering) Air molecules, like oxygen and nitrogen for example, are small in size and thus more effective at scattering shorter wavelengths of light (blue and violet). This produces our blue skies on a clear sunny day. blue skiesblue skies During sunrise and sunset the distance that the light has to travel from the Sun to an observer is at its greatest. This means that a large amount of blue and violet light has been scattered so the light that is received by an observer is mostly of a longer wavelength and therefore appears to be red. Cloud droplets are large enough to scatter all visible wavelengths more or less equally. This means that almost all of the light which enters clouds will be scattered. Because all wavelengths are scattered, clouds appear to be white. Cloud droplets are large enough to scatter all visible wavelengths more or less equally. This means that almost all of the light which enters clouds will be scattered. Because all wavelengths are scattered, clouds appear to be white.wavelengths When clouds become very deep, less and less of the incoming solar radiation makes it through to the bottom of the cloud, which gives these clouds a darker appearance. When clouds become very deep, less and less of the incoming solar radiation makes it through to the bottom of the cloud, which gives these clouds a darker appearance. Greenhouse Effect When Earth's surface is heated, it radiates most of the energy back into the atmosphere as infrared radiation. This IR radiation is absorbed by water vapor, CO 2, methane, and other gases Amount of energy absorbed by atmosphere and earths surface = amount of energy radiated into space https://www.youtube.com/watch?v=ZzCA60 WnoMk https://www.youtube.com/watch?v=ZzCA60 WnoMk Heat Transfer in the Atmosphere Thermal energy - total energy of motion in the particles of a substance Thermal energy - total energy of motion in the particles of a substance Temperature the average thermal energy of the substance particles Temperature the average thermal energy of the substance particles Heat - transfer of thermal energy from a hotter object to a cooler one Heat - transfer of thermal energy from a hotter object to a cooler one Transferred in 1 of 3 ways: Transferred in 1 of 3 ways: Radiation Radiation Conduction Conduction Convection Convection Heating the Troposphere Winds Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure. Wind is the horizontal movement of air from an area of high pressure to an area of lower pressure. Winds are caused by differences in air pressure caused by unequal heating of the atmosphere Wind Direction / Wind Speed Wind speed is measured with an anemometer. Wind speed is measured with an anemometer. The name of a wind tells you the direction the The name of a wind tells you the direction the wind is coming from. wind is coming from. Local Winds - winds that blow over short distances Sea breezes & Sand breezes are Local Winds caused by the unequal heating of Earth's surface within a small area. It takes more energy to warm up a body of water than it does to warm up an equal area of land. Sea Breeze Local wind from an ocean/lake to land During the day, the land warms up faster than the water. The air over land is warmer than air over the water. This warm air expands and rises, creating low pressure area. Cool air blows inland from over the water and moves under the warm air Land Breeze Flow of air from land to a body of water. At night. Land cools more quickly than water. Air over land becomes cooler than air over water. Warmer air over water expands and rises. Cooler air from over land moves beneath this warm air._land_breeze.swf1903page01.cfm Global Winds occur over a large area. Caused by unequal heating of the earth. More concentrated energy falls at the equator. Air over the equator is warmer and less dense than air near the poles. This cause differences in pressure. At the earths surface, global winds blow from poles to equator. Coriolis Effect Because Earth is rotating, global winds do not follow a straight path. The way Earth's rotation makes winds curve is called the Coriolis effect. In the Northern Hemisphere, global winds curve to the right. In the Southern Hemisphere, global winds curve to the left. Because Earth is rotating, global winds do not follow a straight path. The way Earth's rotation makes winds curve is called the Coriolis effect. In the Northern Hemisphere, global winds curve to the right. In the Southern Hemisphere, global winds curve to the left. Calm areas: Calm areas: Doldrums along the equator Doldrums along the equator The sun heats the surface. Warm air rises, cool air moves in but is rapidly heated. Very little pressure difference so very weak winds The Horse Latitudes around 30 N & S no winds The Horse Latitudes around 30 N & S no winds The Winds The Winds 1. Trade winds blow from the NE between Equator & 30 N and from SE between Equator and 30 S blow from the NE between Equator & 30 N and from SE between Equator and 30 S High pressure at 30N and S (horse latitudes); low pressure at equator High pressure at 30N and S (horse latitudes); low pressure at equator Prevailing Westerlies between 30 and 60 N and S between 30 and 60 N and S Blow towards poles Blow towards poles Important for weather of US Important for weather of US Polar Easterlies Cold air near the poles sinks and flows back towards lower latitudes Cold air near the poles sinks and flows back towards lower latitudes Polar Front region where polar eaterlies meet the prevailing westerlies (60N & 60S) effects weather of US Polar Front region where polar eaterlies meet the prevailing westerlies (60N & 60S) effects weather of US Jet Stream High speed wind currents about 200 to 400km per hour High speed wind currents about 200 to 400km per hour km above the surface km above the surface west to east west to east Travel around the earth Travel around the earth Heating Earths Surface Lab Data Time (min.)Temp. Sand C Temp. Water C Time (min.)Temp. Sand C Temp. Water C Start