# Review of Layers of the Atmosphere

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Review of Layers of the Atmosphere

Heat Transfer Heat transfer is the movement of thermal energy from a warmer item to a cooler item. Remember, heat moves in predictable ways, from a high to a low.

The thermal energy goes from HOT areas to COLD. The heat goes OUT
If I open the front door, does the heat go OUT or does the cold come IN? The thermal energy goes from HOT areas to COLD. The heat goes OUT

Heating of the Earth

The Sun provides most of Earth’s energy.

The Sun’s energy can be Reflected back into space by clouds, particles, or Earth’s surface Absorbed by the atmosphere Absorbed by the surface- land and water

This heat energy causes wind and ocean currents.

Three types of heat transfer

Conduction Conduction is heat transfer through solids.
The transfer of heat between substances that are in direct contact.

Examples: Your feet transfer (conduct) heat to a cold tile floor
A spoon placed in hot soup becomes warmer as the spoon conducts heat away from the hot soup

Conduction examples

Conductors are materials that allow heat to pass through easily.
Ex. Metals are the best conductors of heat, whereas air is the worst conductor of heat. Which one(s) are good conductors?

Insulators are materials that do not allow heat to pass through easily
Examples: glass, ceramics and rubber

Which spoon is a conductor? Which spoon is an insulator?
Which spoon would you choose to stir with and why?

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

In the ocean, warm currents move heat from the equator to higher latitudes through convection currents. More direct light at the equator = warmer ocean temperatures at the equator

Convection occurs in fluids
A fluid is defined as a liquid or gas because fluids have the ability to flow from one place to another Solids, however, maintain their position

Convection within the Earth
Divergent 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 heat even when you aren’t in direct contact with it?

Radiation: transfer of heat from one place to another in the form of rays or waves.
Examples heat from the sun, microwave

Heat can travel in waves without a medium (a liquid, solid, or gas).
Radiation is the term that describes heat movement without a medium of matter.

Convection Conduction 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 transfer

Review Videos http://www.wisc-online.com/objects/heattransfer/
(with audio) PBS heat transfer tutorial Heat transfer song, by Mr. Parr