Heat Transfer Conduction Convection Radiation I Thermal Energy

Heat Transfer: Conduction Convection Radiation

I. Thermal Energy A. HEAT (thermal energy) is produced from the motion of molecules. B. The amount of heat depends on how fast the molecules move. C. As molecules move FASTER, more heat is produced. D. Temperature measures how fast (kinetic energy) the molecules are moving.

Question Why is Frosty melting

E. Heat always transfers from a warmer to a cooler object.

II. Heat Transfer Methods: 1. Conduction 2. Convection 3. Radiation

During this video jot down any important info you hear about the 3 types of heat transfer. http: //www. teachertube. com/video/heat-transfer-164366

Conduction & Radiation http: //www. science 4 us. com/elementary-physical-science/energy/heatenergy/? unit=energy&demo=inthelab Cooking with Heat Transfer http: //www. youtube. com/watch? v=QZav. DQii. Ty. I

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

A. Conduction 1. Heat transfers from one object to another object through DIRECT CONTACT. 2. Occurs in SOLIDS. EXAMPLE: Cooking on the stove Conduction = CONTACT

Examples of Conduction:

1. 2. 3. 4. B. CONVECTION 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

Convection Current Cool fluids sink Sink=more dense Rise= less dense Warm fluids rise

Convection current in boiling water Water cools at the surface Hot water rises Cooler water sinks

Examples of Convection: 1. boiling water 2. lava lamp 4. heated air 3. hot air balloon

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.

The third method of heat How does heattransfer energy get from the Sun to the Earth? RADIATION

C. Radiation 1. Heat transferred through space by ELECTROMAGNETIC WAVES 2. Can occur in all states of matter , but radiation does NOT require matter to transfer thermal energy 3. Example: Solar radiation from the Sun Radiation = RAYS

Examples of Radiation: 1. Heat from Sun 3. Infrared heat lamp 2. Cooking in a microwav 4. Heat from fire

Solar Radiation How much of the sun’s radiation do we actually

REVIEW CONDUCTION CONVECTION RADIATION • requires direct • currents in fluids • rays or waves contact • major source: heat • occurs in solids from the sun • does not require • warm fluids matter RISE less dense • cooler fluids SINK more dense • Found in nature Animated Review: https: //www. wisc-online. com/learn/natural-science/earthscience/sce 304/heat-transfer--conduction--convection--radiation

EXAMPLES OF ALL 3 TYPES OF HEAT TRANSFER:

To learn more visit these interactive websites!! Heat Transfer http: //www. pbslearningmedia. org/asset/lsps 07_int_heattrans fer/ Rags to Riches Review Game http: //www. quia. com/rr/544955. html

PRACTICE!! What type of heat transfer is involved? 1. Heating a room with a fireplace 2. Egg cooking in a frying pan 3. Roof of a house becoming hot 4. Sun heating up pavement 5. Walking on hot sand 6. Warm air mass causing a weather change 7. Heating leftovers in a microwave 8. A hot air balloon taking flight 9. Picking up a hot cup of coffee 10. Drives continental drift (the spreading of continents)

CHECK YOU ANSWERS!! 1. Convection 2. Conduction 3. Radiation 4. Radiation 5. Conduction 6. Convection 7. Radiation 8. Convection 9. Conduction 10. Convection

1. Which of the following is not a method of heat transfer? A. Radiation B. Insulation C. Conduction D. Convection

2. In which of the following are the particles closest together? A. Solid B. Liquid C. Gas D. Fluid

3. How does heat energy reach the Earth from the Sun? A. Radiation B. Conduction C. Convection D. Insulation

4. Which is the best surface for reflecting heat radiation? A. Shiny white B. Dull white C. Shiny black D. Dull black

5. Which is the best surface for absorbing heat radiation? A. Shiny white B. Dull white C. Shiny black D. Dull black