Transcription
Conduction, Convection, andRadiation
What is heat? Another name for heat is thermal energy. Heat is the total amount of energy ofmotion in the molecules of a substance. EVERY molecule is always moving.soEVERY molecule ALWAYS HAS HEAT!
How is heat measured? Heat is measured in units called calories. A calorie is the quantity of heat required toraise the temperature of one gram of waterone degree Celsius. Adding heat makes the molecules movefaster, and therefore increases thetemperature.
What is temperature? Temperature is the average amount ofenergy of motion in the molecules of asubstance. Temperature is HOW MUCH each moleculeis moving.the SPEED of the motion.
How is temperature measured? Heat is measured in units called degrees. On the Celsius scale, the freezing point ofwater is degrees while the boilingpoint is degrees.
All energy on Earth begins with theSun.How is that energy distributed?5% is reflected by Earth’s surface.25% is reflected by clouds and the atmosphere.20% is absorbed by clouds and the atmosphere.50% is absorbed by the Earth’s surface.
Heat Transfer Heat always moves from a warmer place to acooler place. Heat moves through three methods: Conduction Convection Radiation
RadiationHow does heatenergy get from the There are noparticles betweenSun to the Earth?the Sun and theEarth so it CANNOTtravel by conduction?or by convection.
RADIATION When electromagnetic waves travelthrough space, it is calledRadiation. When electromagneticwaves come in contact with anobject, the waves transfer the heatto the object. Electromagneticwaves travel through emptyspace.Can you think of other examples of radiation?Discuss before going to the next slide!
RADIATION A Camp Fire A MicrowaveOven A Lightbulb
CONDUCTION Conduction is thetransfer of heat betweensubstances in directcontat with each other.The better the conductor,the more rapidly heat willtransfer.
CONDUCTORS What substances doyou think would begood conductors orpoor conductors?Copper SteelWoodIronPaperAirStyrofoamSteel
GOOD CONDUCTORS: Steel Silver Iron Copper
Conduction is the transfer of heat energy fromone substance to another byDIRECT CONTACT.The air above the Earth’s surface warms bycontact with the warm surface.Conduction
ConvectionConvectionIs the transfer of energy from place to place bythe motion of gas or liquid. The motion of gasesup and down.Differences in density produce the motion of airconvection.Warm air: LOW densityCold air: HIGH density
CONVECTION Convection is the upand down movementof gases and liquidsby heat transfer.
CONVECTION As a gas or liquid isheated, it warms,expands, and risesbecause it is lessdense. When the gasor liquid cools, itbecomes denser andfalls.
CONVECTION This creates aCONVECTIONCURRENT.Convection is theprimary method bywhich heat movesthrough gases andliquids.
CONVECTION As a gas or liquid isheated, it warms,expands, and risesbecause it is lessdense. When the gasor liquid cools, itbecomes denser andfalls.Can you think of other examples of convection?Discuss before going to the next slide!
CONVECTION Other examples: Warmer water at the surface ofa lake or swimming pool Hot Air Balloon Wind Currents Lower floors of a buildingbeing cooler than the top floor
Conduction is the transfer of heat energy from one substance to another by DIRECT CONTACT. The air above the Earth’s surface warms by contact with the warm surface. Conduction . Convection Convection Is the transfer of energy from place to
