Review of Layers of the Review of Layers of the Atmosphere Atmosphere

http://studyjams.scholastic.com/studyjams/jams/science/weather-and-climate/earths-atmosphere.htm

Heat TransferHeat Transfer

Heat transferHeat transfer is the movement of is the movement of thermal energy from a warmer item thermal energy from a warmer item to a cooler item. to a cooler item.

Remember, heat moves in Remember, heat moves in predictable ways, from a predictable ways, from a highhigh to a to a lowlow. .

If I open the front door, does the If I open the front door, does the heat go OUT or does the cold heat go OUT or does the cold

come IN?come IN?

The thermal energy goes

from HOT areas to

COLD. The heat goes

OUT

Heating of the EarthHeating of the Earth

The Sun provides most of Earth’s energy.The Sun provides most of Earth’s energy.

The Sun’s energy can beThe Sun’s energy can be– Reflected back into space by clouds, particles, Reflected back into space by clouds, particles,

or Earth’s surfaceor Earth’s surface– Absorbed by the atmosphereAbsorbed by the atmosphere– Absorbed by the surface- land and waterAbsorbed by the surface- land and water

This heat energy causes wind and ocean This heat energy causes wind and ocean currents.currents.

Three types of heat transferThree types of heat transfer

ConductionConduction

ConvectionConvection

RadiationRadiation

ConductionConduction ConductionConduction is heat transfer through is heat transfer through

solids.solids. The transfer of heat between The transfer of heat between

substances that are in substances that are in directdirect contact. contact.

Examples:Examples: Your feet transfer Your feet transfer

((conductconduct) heat to a cold ) heat to a cold tile floor tile floor

A spoon placed in hot A spoon placed in hot soup becomes warmer as soup becomes warmer as the spoon the spoon conducts conducts heat heat away from the hot soup away from the hot soup

Conduction examplesConduction examples

Conductors are Conductors are materials that allow materials that allow heat to pass through heat to pass through easily.easily.

Ex. Ex. Metals are the Metals are the best conductors of best conductors of heat, whereas air is heat, whereas air is the worst the worst conductor of heat.conductor of heat.

Which one(s) are Which one(s) are good conductors?good conductors?

Insulators are Insulators are materials that do materials that do not allow heat to not allow heat to pass through pass through easilyeasily

Examples: glass, Examples: glass, ceramics and ceramics and rubberrubber

Which spoon is a conductor? Which spoon Which spoon is a conductor? Which spoon is an insulator?is an insulator?

Which spoon would you choose to stir with Which spoon would you choose to stir with and why?and why?

–ConvectionConvection: transfer of heat : transfer of heat from one place to another from one place to another through circulation of material.through circulation of material.Example, heat flowing through Example, heat flowing through air or waterair or water

In the ocean, warm currents move heat In the ocean, warm currents move heat from the equator to higher latitudes from the equator to higher latitudes

through through convectionconvection currents. currents.

More direct light at the equator = warmer ocean

temperatures at the

equator

ConvectionConvection occurs in fluids occurs in fluids A A fluidfluid is defined as a liquid or gas is defined as a liquid or gas

because fluids have the ability to flow because fluids have the ability to flow from one place to anotherfrom one place to another

Solids, however, maintain their Solids, however, maintain their positionposition

Convection within the EarthConvection within the EarthDivergent Boundary

Mid Ocean Ridge

Convergent Boundary

Trench

Material in the

mantle is heated by the outer core and it rises, pushing apart the plates of the crust

How do you feel the Sun’s How do you feel the Sun’s heat even when you aren’t heat even when you aren’t in direct contact with it?in direct contact with it?

RadiationRadiation: : transfer of heat transfer of heat from one place to another in from one place to another in the form of rays or wavesthe form of rays or waves. .

Examples heat from the sun, Examples heat from the sun, microwave microwave

Heat can travel in waves without a Heat can travel in waves without a medium (a liquid, solid, or gas).medium (a liquid, solid, or gas).

RadiationRadiation is the term that describes is the term that describes heat movement without a medium of heat movement without a medium of matter.matter.

ReviewReview ConductionConduction ConvectionConvection RadiationRadiation

Convection

Conduction

Conduction

Convection

Radiation

Radiation

Conduction

Can you explain why you feel warm when you are standing away from a campfire?– Radiation

Why does a carpeted floor feel warmer to bare feet than tile even though both surfaces are the same temperature?– Better conductor

What information would you need in order to predict whether heat transfer would occur when two objects or materials interact?– Are they the same temperature? If no, then heat

will flow from the hotter object to the colder one.– Is it an insulating material or a conducting

material? If it is insulating, there will be little or no heat transfer.

Name each type of heat transferName each type of heat transfer

Review VideosReview Videos

http://www.wisc-online.com/objects/http://www.wisc-online.com/objects/heattransfer/heattransfer/

(with audio)(with audio) http://vitalnj.pbslearningmedia.org/asset/http://vitalnj.pbslearningmedia.org/asset/

lsps07_int_heattransfer/lsps07_int_heattransfer/ PBS heat transfer tutorial PBS heat transfer tutorial http://www.youtube.com/watch?http://www.youtube.com/watch?v=wr8Z4SCETPsv=wr8Z4SCETPsHeat transfer song, by Mr. ParrHeat transfer song, by Mr. Parr