H EAT T RANSFER Chapter 22

RECAP Heat is ALWAYS transferred from Objects of temperatures that are brought near one another until all have a

C ONDUCTION Can take place that are in Materials that conduct heat well are known as Collisions between When one part is, atoms start to until all atoms are Free electrons that can drift are made to and Materials with

Touch the faucet and touch the wooden drawer Which is cooler? Is it really? What temperature are both of them at? What is really happening? WOOD VERSUS METAL

Wood is heat conductors are called Objects that No can TOTALLY It at which heat Liquids and gases tend to be Porous materials are Heat is &  Cold is NOT energy;

C ONVECTION Movement of i.e. a pot of water of the stove demonstration on p327 Occurs in When fluid is, it, becomes less ~ Archimedes’ Principle Warmer fluid is by Cooler fluid moves to the Keeps fluid

Convection currents are produced by Some areas of the earth more readily than others Land is than water in the day air from above water takes the place of warmer air, Land is than the water at night

W HY R ISING W ARM A IR C OOLS Rising Less atmospheric air heats up Molecules in a region with than with approaching ones Rebound speed

R ADIATION Radiant energy Any energy that is In the form of Radio waves, microwaves, infrared, visible light, UV, X rays, gamma rays ( Measured in

All objects continually emit in a mixture of obj = If obj is hot enough, Lamp filament, sun, fireplace all If radiant energy falls on other objects, part of energy is Absorbed part increases