6.2 Transferring Thermal Energy

6.2 Transferring Thermal 6.2 Transferring Thermal EnergyEnergy

ConductionConduction Transfer of thermal Transfer of thermal energy (TE) by energy (TE) by collisions between the collisions between the particles in matterparticles in matter

Kinetic energy is Kinetic energy is transferred when transferred when faster moving particles faster moving particles bump into slower bump into slower moving particlesmoving particles

This can happen in This can happen in solids, liquids and solids, liquids and gases, but since solid’s gases, but since solid’s particles are closer particles are closer together, solids are together, solids are able to conduct heat able to conduct heat better than liquids and better than liquids and gasesgases

ConvectionConvection Transfer of E by the Transfer of E by the

movement of movement of mattermatter

Liquids and gases Liquids and gases can flow , so their can flow , so their particles can move particles can move from one place to from one place to another, carrying E another, carrying E with themwith them

When heating a When heating a liquid a convection liquid a convection current forms, rises, current forms, rises, then cools and sinksthen cools and sinks

RadiationRadiation Transfer of E by Transfer of E by

electromagnetic waveselectromagnetic waves Does NOT require matter for Does NOT require matter for

heat transferheat transfer How the sun warms the Earth How the sun warms the Earth

from 150 million Kilometers from 150 million Kilometers away!away!

Called radiant ECalled radiant E 34% reflects back into space34% reflects back into space Only RE that is absorbed Only RE that is absorbed

changes into thermal Echanges into thermal E Different materials absorb RE Different materials absorb RE

differently: Shiny: reflectsdifferently: Shiny: reflects Dull: absorbsDull: absorbs Dark colors absorb more than Dark colors absorb more than

light colorslight colors