HEAT TRANSFER IN THE ATMOSPHERE
REVIEWREVIEW• TEMPERATURETEMPERATURE
• THE AVERAGE AMOUNT OF THE AVERAGE AMOUNT OF ENERGYENERGY OF MOTION OF EACH PARTICLE IN OF MOTION OF EACH PARTICLE IN A SUBSTANCE.A SUBSTANCE.
• HEAT TRANSFER TYPESHEAT TRANSFER TYPES– CONDUCTIONCONDUCTION = = HEAT TRANSFER BY OBJECTS IN HEAT TRANSFER BY OBJECTS IN DIRECT CONTACT DIRECT CONTACT WITH EACH OTHERWITH EACH OTHER
– CONVECTIONCONVECTION = HEAT TRANSFER BY THE = HEAT TRANSFER BY THE MOVEMENTMOVEMENT OF MOLECULES IN A OF MOLECULES IN A FLUIDFLUID
– RADIATIONRADIATION = HEAT TRANSFER = HEAT TRANSFER WITHOUT WITHOUT THE OBJECTS COMING IN CONTACT WITH THE OBJECTS COMING IN CONTACT WITH EACH OTHEREACH OTHER
WHAT HAPPENS TO WHAT HAPPENS TO DENSITY WHEN DENSITY WHEN
TEMPERATURE INCREASES?TEMPERATURE INCREASES?
WHAT HAPPENS TO WHAT HAPPENS TO DENSITY WHEN DENSITY WHEN
TEMPERATURE DECREASES?TEMPERATURE DECREASES?
CHANGES IN PHASES OF CHANGES IN PHASES OF MATTERMATTER
TEMPERATURE AND ENERGY INCREASING
TEMPERATURE AND ENERGY DECREASING
GAS
LIQUIDSOLID
Phase Changes
In order to change from: A substance must: The molecules move:
Solid to Liquid Increase heat energy
Faster and farther apart
Liquid to Gas Increase heat energy
Faster and farther apart
Gas to Liquid Decrease heat energy
Slower and closer together
Liquid to Solid Decrease heat energy
Slower and closer together
HEAT TRANSFER AT THE HEAT TRANSFER AT THE MOLECULAR LEVELMOLECULAR LEVEL
• MOLECULES WITHIN A SUBSTANCE MOLECULES WITHIN A SUBSTANCE TRANSFER THEIR HEAT ENERGY WHEN TRANSFER THEIR HEAT ENERGY WHEN THEY THEY COLLIDE COLLIDE WITH EACH OTHERWITH EACH OTHER
• THE CLOSER MOLECULES ARE (more THE CLOSER MOLECULES ARE (more dense), THE dense), THE FASTER FASTER HEAT ENERGY HEAT ENERGY WILL BE TRANSFERREDWILL BE TRANSFERRED
• ASSUMING THAT THE DIFFERENT ASSUMING THAT THE DIFFERENT PHASES ARE MADE OF THE SAME PHASES ARE MADE OF THE SAME SUBSTANCE, SUBSTANCE, SOLIDSSOLIDS TRANSFER HEAT TRANSFER HEAT FASTEST, FOLLOWED BY FASTEST, FOLLOWED BY LIQUIDSLIQUIDS, AND , AND GASESGASES ARE THE SLOWEST ARE THE SLOWEST
TEMPERATURE VS. DENSITY TEMPERATURE VS. DENSITY CONTINUEDCONTINUED
• EVEN WITHIN THE SAME STATE OF MATTER, EVEN WITHIN THE SAME STATE OF MATTER, WARMER SUBSTANCES EXPAND AND BECOME WARMER SUBSTANCES EXPAND AND BECOME LESS DENSE THAN COOLER SUBSTANCESLESS DENSE THAN COOLER SUBSTANCES
THE EIFFEL TOWER IS 8 THE EIFFEL TOWER IS 8 INCHES TALLER IN THE INCHES TALLER IN THE SUMMER THAN IN THE SUMMER THAN IN THE
WINTERWINTER
HOT WATER AT THE HOT WATER AT THE BOTTOM OF A POT OF BOTTOM OF A POT OF BOILING WATER RISES BOILING WATER RISES WHILE COOL WATER WHILE COOL WATER FROM THE TOP SINKS FROM THE TOP SINKS
(CREATES CONVECTION (CREATES CONVECTION CURRENTS)CURRENTS)
WARM AIR RISES AND WARM AIR RISES AND COOL AIR SINKS COOL AIR SINKS
(CREATES (CREATES CONVECTION CONVECTION CURRENTS)CURRENTS)
CONVECTION CURRENTS CONVECTION CURRENTS UNDERGROUNDUNDERGROUND
MAGMA IS MAGMA IS HEATEDHEATED BY THE BY THE EARTH’S COREEARTH’S CORE
AS MAGMA AS MAGMA EXPANDSEXPANDS
FROM THE FROM THE ADDITIONAL ADDITIONAL
HEAT, IT HEAT, IT BECOMES BECOMES
LESSLESS DENSE DENSE AND RISES AND RISES
TO THE TO THE SURFACESURFACE
MAGMA LOSES MAGMA LOSES HEAT ENERGY HEAT ENERGY TO THE TO THE CRUST AS IT PUSHES THE SURFACE PLATESCRUST AS IT PUSHES THE SURFACE PLATES
AS THE AS THE MAGMA MAGMA COOLS, IT COOLS, IT CONTRACTS CONTRACTS AND AND BECOMES BECOMES MOREMORE DENSE DENSE SO IT SO IT SINKSSINKS BACK BACK TOWARD THE TOWARD THE CORECORE
CONVECTION CURRENTS IN CONVECTION CURRENTS IN THE AIRTHE AIR
THE COOLER AIR RUSHES TO FILL THE VOID THE COOLER AIR RUSHES TO FILL THE VOID LEFT BY THE RISING WARM AIR (CREATING LEFT BY THE RISING WARM AIR (CREATING
WINDWIND))
THE WARM AIR THE WARM AIR COOLSCOOLS AS IT RISES AS IT RISES (TEMPERATURES IN THE TROPOSPHERE (TEMPERATURES IN THE TROPOSPHERE
FALL AS ALTITUDE INCREASES) FALL AS ALTITUDE INCREASES)
AS THE AIR AS THE AIR COOLS, IT COOLS, IT CONTRACTSCONTRACTS AND FALLS AND FALLS BACK TOWARD BACK TOWARD EARTH’S EARTH’S SURFACESURFACE
AS THE AIR IS AS THE AIR IS WARMED BY WARMED BY
HEATHEAT RADIATING RADIATING BACK FROM THE BACK FROM THE
EARTH, IT EARTH, IT EXPANDS AND EXPANDS AND
RISESRISES
TEMPERATURE VS. TEMPERATURE VS. ALTITUDEALTITUDE
• AS ALTITUDE INCREASES:AS ALTITUDE INCREASES:
• TEMPERATURE IN THE TEMPERATURE IN THE TROPOSPHERE TROPOSPHERE DECREASESDECREASES
• TEMPERATURE IN THE TEMPERATURE IN THE STRATOSPHERE STRATOSPHERE INCREASESINCREASES
• TEMPERATURE IN THE TEMPERATURE IN THE MESOSPHERE MESOSPHERE DECREASESDECREASES
• TEMPERATURE IN THE TEMPERATURE IN THE THERMOSPHERE THERMOSPHERE INCREASESINCREASES
WHY DOES TEMPERATURE WHY DOES TEMPERATURE FALL AS YOU GO UP IN THE FALL AS YOU GO UP IN THE
TROPOSPHERE?TROPOSPHERE?• EARTH’S EARTH’S SURFACE SURFACE IS HEATED BY RADIATION FROM THE SUN (SOLIDS AND IS HEATED BY RADIATION FROM THE SUN (SOLIDS AND
LIQUIDS HEAT MORE QUICKLY THAN GASES)LIQUIDS HEAT MORE QUICKLY THAN GASES)
• AIR IN THE LOWER TROPOSPHERE IS WARMED BY HEAT AIR IN THE LOWER TROPOSPHERE IS WARMED BY HEAT RADIATING RADIATING BACK OFF BACK OFF OF EARTH’S SURFACEOF EARTH’S SURFACE
• RADIATED HEAT IS TRAPPED BY “RADIATED HEAT IS TRAPPED BY “GREENHOUSE GASES” (GREENHOUSE GASES” (MOSTLY MOSTLY COCO22 AND AND METHANE)METHANE)
• GREENHOUSE GASES ARE FOUND IN GREENHOUSE GASES ARE FOUND IN THEIR HIGHEST CONCENTRATIONS THEIR HIGHEST CONCENTRATIONS CLOSE CLOSE TO THE EARTH’S SURFACETO THE EARTH’S SURFACE
• THERE IS NOT ENOUGH RADIATED THERE IS NOT ENOUGH RADIATED HEAT HEAT ENERGYENERGY LEFT TO HEAT THE LEFT TO HEAT THE AIR IN THE UPPER TROPOSPHEREAIR IN THE UPPER TROPOSPHERE
WHY DOES TEMPERATURE WHY DOES TEMPERATURE RISE AS YOU GO UP IN THE RISE AS YOU GO UP IN THE
STRATOSPHERE?STRATOSPHERE?• UPPER LAYER OF STRATOSPHERE HAS HIGH CONCENTRATION
OF OZONE (OZONE LAYER)
• OZONE ABSORBS ENERGY FROM UV RADIATION FROM THE SUN
• EXTRA ENERGY CAUSES MOLECULES TO MOVE FASTER AND COLLIDE MORE, WHICH LEADS TO HIGHER TEMPERATURES
WHY DOES TEMPERATURE WHY DOES TEMPERATURE FALL AS YOU GO UP IN THE FALL AS YOU GO UP IN THE
MESOSPHERE?MESOSPHERE?• THE MOLECULES IN THE MESOSPHERE ARE SPREAD VERY FAR
APART (LOW DENSITY)– DESPITE ITS LOW DENSITY, IT IS STILL MORE DENSE THAN
THE NEXT LAYER ABOVE IT (THE THERMOSPHERE) WHICH IS WHY METEOROIDS BURN UP FROM THE FRICTION HERE
• AS A RESULT, THE MOLECULES DO NOT COLLIDE OFTEN
• FEWER COLLISIONS OF MOLECULES RELEASES LESS HEAT, SO TEMPERATURES ARE LOWER
WHY DOES TEMPERATURE WHY DOES TEMPERATURE RISE AS YOU GO UP IN THE RISE AS YOU GO UP IN THE
THERMOSPHERE?THERMOSPHERE?• THE THERMOSPHERE IS THE OUTERMOST LAYER OF EARTH’S
ATMOSPHERE SO IT IS SUBJECTED TO MORE DIRECT SOLAR RADIATION THAN ANY OTHER LAYER
• THIS EXTREME RADIATION LEADS TO THE IONIZATION (LOSING AND GAINING ELECTRONS) OF MANY AIR MOLECULES– THESE IONS ARE RESPONSIBLE FOR THE AURORA BOREALIS
(NORTHERN LIGHTS)
• IONS TEND TO ABSORB AND CONDUCT ENERGY (INCLUDING HEAT ENERGY) VERY WELL SO THE TEMPERATURE RISES• BECAUSE THE DENSITY OF
THIS LAYER IS SO LOW, YOU COULD ACTUALLY FREEZE TO DEATH DESPITE THE 1000oC TEMPERATURES (NOT ENOUGH MOLECULES TO TRANSFER HEAT TO YOUR SKIN)