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Heat Transfer: Conduction Convection Radiation
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I. Thermal Energy HEAT (thermal energy) is produced from the motion of molecules. The amount of heat depends on how fast the molecules move. As molecules move FASTER, more heat is produced. Temperature measures how fast (kinetic energy) the molecules are moving.
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Question Why is Frosty melting
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E. Heat always transfers from a warmer to a cooler object.
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II. Heat Transfer Methods:
Conduction Convection Radiation
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During this video jot down any important info you hear about the 3 types of heat transfer.
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Conduction & Radiation Cooking with Heat Transfer
Cooking with Heat Transfer
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When you heat a metal strip at one end, the heat travels to the other end.
As the metal is heated, the particles vibrate. These vibrations pass thermal energy along the metal causing it to heat up. This is called Conduction.
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A. Conduction Conduction = CONTACT
Heat transfers from one object to another object through DIRECT CONTACT. Occurs in SOLIDS. EXAMPLE: Cooking on the stove Conduction = CONTACT
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Examples of Conduction:
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B. CONVECTION Convection = VENTS
Heat transfer in FLUIDS (liquids or gases) Heat is transferred through CURRENTS . Warm fluids RISE bc they’re less dense Cooler fluids SINK bc they’re more dense. Convection Current Convection = VENTS
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Convection Current Cool fluids sink Warm fluids rise Sink=more dense
Rise= less dense Warm fluids rise
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Convection current in boiling water
Water cools at the surface Hot water rises Cooler water sinks
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Examples of Convection:
1. boiling water 2. lava lamp 3. hot air balloon 4. heated air
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Convection currents in nature
Convection currents in the atmosphere are responsible for our weather. Convection currents cause the cooler breezes you experience by a large body of water. Convection currents also cause the movement of magma within the earth.
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The third method of heat transfer
How does heat energy get from the Sun to the Earth? RADIATION
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C. Radiation Radiation = RAYS
Heat transferred through space by ELECTROMAGNETIC WAVES Can occur in all states of matter , but radiation does NOT require matter to transfer thermal energy Example: Solar radiation from the Sun Radiation = RAYS
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Examples of Radiation:
2. Cooking in a microwave 1. Heat from Sun 3. Infrared heat lamp 4. Heat from fire
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How much of the sun’s radiation do we actually receive?
Solar Radiation How much of the sun’s radiation do we actually receive?
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REVIEW Animated Review: CONDUCTION CONVECTION RADIATION
requires direct contact occurs in solids currents in fluids warm fluids RISE less dense cooler fluids SINK more dense Found in nature rays or waves major source: heat from the sun does not require matter Animated Review:
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EXAMPLES OF ALL 3 TYPES OF HEAT TRANSFER:
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To learn more visit these interactive websites
To learn more visit these interactive websites!! Heat Transfer Rags to Riches Review Game
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PRACTICE!! What type of heat transfer is involved?
Heating a room with a fireplace Egg cooking in a frying pan Roof of a house becoming hot Sun heating up pavement Walking on hot sand Warm air mass causing a weather change Heating leftovers in a microwave A hot air balloon taking flight Picking up a hot cup of coffee Drives continental drift (the spreading of continents)
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CHECK YOU ANSWERS!! Convection Conduction Radiation
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1. Which of the following is not a method of heat transfer?
A. Radiation B. Insulation C. Conduction D. Convection
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2. In which of the following are the particles closest together?
A. Solid B. Liquid C. Gas D. Fluid
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3. How does heat energy reach the Earth from the Sun?
A. Radiation B. Conduction C. Convection D. Insulation
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4. Which is the best surface for reflecting heat radiation?
A. Shiny white B. Dull white C. Shiny black D. Dull black
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5. Which is the best surface for absorbing heat radiation?
A. Shiny white B. Dull white C. Shiny black D. Dull black
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