Warm Up 3/6/08 Warm Up 3/6/08 1) More solar energy reaches the equatorial regions than the polar regions because the equatorial regions a. are covered by a greater area of land. b. have more vegetation to absorb sunlight. c. receive sun rays closest to vertical. d. have days with more hours of sunlight. 2) Most important weather phenomena occur in the ____. a. stratosphere c. mesosphere b. thermosphere d. troposphere 3) The form of oxygen that combines three oxygen atoms into each molecule is called ____. a. ozonec. thermopause b. argond. chlorofluorocarbon Answers: 1) c. 2) d. 3) a. Answers: 1) c. 2) d. 3) a.
Transcript
Warm Up 3/6/08Warm Up 3/6/081) More solar energy reaches the equatorial regions
than the polar regions because the equatorial regionsa. are covered by a greater area of land.b. have more vegetation to absorb sunlight.c. receive sun rays closest to vertical.d. have days with more hours of sunlight.
2) Most important weather phenomena occur in the ____.a. stratosphere c. mesosphereb. thermosphere d. troposphere
3) The form of oxygen that combines three oxygen atoms into each molecule is called ____.a. ozone c. thermopauseb. argon d. chlorofluorocarbon
Answers: 1) c. 2) d. 3) a.Answers: 1) c. 2) d. 3) a.
Heating the Heating the AtmosphereAtmosphere
Chapter 17, Section 2Chapter 17, Section 2
Energy Transfer as HeatEnergy Transfer as Heat
Heat –Heat – the energy transferred from the energy transferred from one object to another because of a one object to another because of a difference in their temperaturesdifference in their temperatures
Temperature –Temperature – measure of the measure of the kinetic energy (energy of motion) of kinetic energy (energy of motion) of the individual atoms or molecules in the individual atoms or molecules in a substancea substance
Three mechanisms of energy transfer Three mechanisms of energy transfer as heat are conduction, convection, as heat are conduction, convection, and radiationand radiation
Heat TransferHeat Transfer
ConductionConduction Conduction –Conduction – the transfer of heat through the transfer of heat through
matter by molecular activitymatter by molecular activity The energy of molecules is transferred by The energy of molecules is transferred by
collisions from one molecule to anothercollisions from one molecule to another Heat flows from the higher temperature Heat flows from the higher temperature
matter to the lower temperature mattermatter to the lower temperature matter Different materials conduct heat better Different materials conduct heat better
than othersthan others Metals are good conductors, while air is a Metals are good conductors, while air is a
poor conductor of heatpoor conductor of heat Conduction is only important between Conduction is only important between
Earth’s surface and the air directly in Earth’s surface and the air directly in contact with the surfacecontact with the surface
ConductionConduction
ConvectionConvection Much of the heat transfer that occurs in the Much of the heat transfer that occurs in the
atmosphere is carried on by convectionatmosphere is carried on by convection Convection –Convection – the transfer of heat by mass the transfer of heat by mass
movement or circulation within a substancemovement or circulation within a substance Convection takes place in fluids, like the Convection takes place in fluids, like the
ocean and air, where the atoms and ocean and air, where the atoms and molecules are free to move aboutmolecules are free to move about
Convection also takes place in solids, such Convection also takes place in solids, such as Earth’s mantle, which behave as fluids as Earth’s mantle, which behave as fluids over long periods of timeover long periods of time
Most of the heat acquired by radiation and Most of the heat acquired by radiation and conduction in the lowest layer of the conduction in the lowest layer of the atmosphere is transferred by convective atmosphere is transferred by convective flowflow
ConvectionConvection
Concept CheckConcept Check
What is convection?What is convection? Convection is the transfer of heat by Convection is the transfer of heat by
mass movement or circulation within mass movement or circulation within a substance.a substance.
Electromagnetic WavesElectromagnetic Waves The sun is the ultimate source of energy that The sun is the ultimate source of energy that
creates our weathercreates our weather All radiation from the sun (electromagnetic All radiation from the sun (electromagnetic
waves), whether X-rays, radio waves, or heat waves), whether X-rays, radio waves, or heat waves, travel through the vacuum of space at waves, travel through the vacuum of space at 300,000 km/s (only slightly slower through our 300,000 km/s (only slightly slower through our atmosphere)atmosphere)
Electromagnetic waves move outward from Electromagnetic waves move outward from their source and come in a variety of sizestheir source and come in a variety of sizes
The most important difference between types The most important difference between types is their wavelength (Radio waves have the is their wavelength (Radio waves have the longest, and Gamma waves have the shortest)longest, and Gamma waves have the shortest)
Visible light is a small part of this Visible light is a small part of this electromagnetic spectrum (each color electromagnetic spectrum (each color corresponds to a specific wavelength of visible corresponds to a specific wavelength of visible light), the combination of which is white lightlight), the combination of which is white light
Electromagnetic SpectrumElectromagnetic Spectrum
Concept CheckConcept Check
Which electromagnetic wave has the Which electromagnetic wave has the longest wavelength?longest wavelength?
Radio WavesRadio Waves
RadiationRadiation Radiation –Radiation – the transfer of energy (heat) the transfer of energy (heat)
through space by electromagnetic wavesthrough space by electromagnetic waves Unlike conduction and convection, Unlike conduction and convection,
radiant energy can travel through the radiant energy can travel through the vacuum of spacevacuum of space
The four laws governing radiationThe four laws governing radiation1.1. All objects, at any temperature, emit All objects, at any temperature, emit
radiant energyradiant energy2.2. Hotter objects radiate more total energy Hotter objects radiate more total energy
per unit area than colder objects doper unit area than colder objects do3.3. The hottest radiating bodies produce the The hottest radiating bodies produce the
shortest wavelengths of maximum shortest wavelengths of maximum radiationradiation
4.4. Objects that are good absorbers of Objects that are good absorbers of radiation are good emitters as wellradiation are good emitters as well
Three Mechanisms of Heat Three Mechanisms of Heat TransferTransfer
What Happens to Solar What Happens to Solar Radiation?Radiation?
When radiation strikes an object, there When radiation strikes an object, there usually are three different resultsusually are three different results
1.1. Some energy is absorbed by the objectSome energy is absorbed by the object
2.2. Substances such as water and air are Substances such as water and air are transparent to certain wavelengths of transparent to certain wavelengths of radiationradiation
3.3. Some radiation may bounce off the Some radiation may bounce off the object without being absorbed or object without being absorbed or transmittedtransmitted
Reflection and ScatteringReflection and Scattering Reflection –Reflection – occurs when light bounces off occurs when light bounces off
an objectan object The reflected radiation has the same The reflected radiation has the same
intensity as the incident (coming in) intensity as the incident (coming in) radiationradiation
Scattering –Scattering – produces a larger number of produces a larger number of weaker rays that travel in different directionsweaker rays that travel in different directions
About 30 % of solar energy is reflected back About 30 % of solar energy is reflected back into space, this energy is lost and doesn’t go into space, this energy is lost and doesn’t go into heating the atmosphereinto heating the atmosphere
Small particles in the atmosphere also help Small particles in the atmosphere also help scatter solar radiationscatter solar radiation
About half of the solar radiation that is About half of the solar radiation that is absorbed at Earth’s surface arrives as absorbed at Earth’s surface arrives as scattered lightscattered light
Reflection and ScatteringReflection and Scattering
Concept CheckConcept Check
How much solar energy is reflected How much solar energy is reflected back to space?back to space?
30%30%
AbsorptionAbsorption About 50 % of the solar energy that strikes the top of the About 50 % of the solar energy that strikes the top of the
atmosphere reaches Earth’s surface and is absorbed, then atmosphere reaches Earth’s surface and is absorbed, then is redirected skywardis redirected skyward
The atmosphere absorbs the longer wavelengths emitted The atmosphere absorbs the longer wavelengths emitted by Earth, with water vapor and carbon dioxideby Earth, with water vapor and carbon dioxide
Gases in the atmosphere will eventually radiate away Gases in the atmosphere will eventually radiate away some of this energysome of this energy
Earth’s surface is continually supplied with heat from the Earth’s surface is continually supplied with heat from the atmosphere as well as from the sunatmosphere as well as from the sun
Greenhouse Effect –Greenhouse Effect – the heating of Earth’s surface and the heating of Earth’s surface and atmosphere from solar radiation being absorbed and atmosphere from solar radiation being absorbed and emitted by the atmosphere, mainly by water vapor and emitted by the atmosphere, mainly by water vapor and carbon dioxidecarbon dioxide
Some incoming solar radiation is not absorbed and Some incoming solar radiation is not absorbed and reradiated, but instead is used by plants for reradiated, but instead is used by plants for photosynthesisphotosynthesis
Solar energy is the main energy source for virtually all life Solar energy is the main energy source for virtually all life on Earthon Earth
Heating of the AtmosphereHeating of the Atmosphere
Distribution of Incoming Solar Distribution of Incoming Solar RadiationRadiation
1.1. List and describe the three major List and describe the three major mechanisms of heat transfer in the mechanisms of heat transfer in the atmosphere.atmosphere.
2.2. Dark objects tend to absorb more Dark objects tend to absorb more radiation than light-colored objects. radiation than light-colored objects. Explain whether dark objects or Explain whether dark objects or light objects on Earth’s surface light objects on Earth’s surface would be better radiators of heat.would be better radiators of heat.
3.3. What is one thing new that you What is one thing new that you learned today? Explain.learned today? Explain.
