HEAT!Convection, Conduction, and

Radiation

HEAT Heat is…

Thermal energy in transit (moving!)

Molecules are moving and bouncing around –

the faster they go – the hotter it gets!

Energy ALWAYS transfers from warmer matter to cooler matter until both reach the same temperature

HEAT Heat always moves from a warmer place

to a cooler place.Hot objects in a cooler room will cool to

room temperature.Cold objects in a warmer room will heat up

to room temperature

If a cup of coffee were left on the table in this room what would happen to it?

If two scoops of Orange Leaf frozen yogurt was left on the table in this room what would happen to it?

HEAT Energy moves from one place to

another… Three ways for heat to transfer

ConductionConvectionRadiation

CONDUCTION The process by which heat energy

travels through solids. Heat transfers thanks to direct contact

with matter of a higher temperature Matter must be present and touching

HOW CONVECTION WORKS If one end of a solid material is heated,

heat energy passes into it. As this happens, the particles in the heated end of the solid vibrate more quickly and strongly. Because the particles are packed tightly together, they bump into neighboring particles then begin to vibrate more quickly and vigorously, and in turn they bump into particles close to them. In this way heat is transferred along the length of the solid. As this happens, the solid becomes warmer throughout.

CONDUCTION

Process where heat energy is transferred by physical contact through a substance. Particles of a substance have to touch each other to pass heat from warmer to cooler.

Warmer area,Lots of KE

Cooler area,gaining KE…warming up

Collision of particles

CONDUCTION Think…hot blacktop! When you walk on the black asphalt in

the summer and it scorches your feet… PERFECT example of conduction

CONDUCTION A good conductor is a substance that

allows heat to transfer through it easily.

A bad conductor (Insulator) is a substance that does NOT allow heat to transfer very well toward the cooler area.

CONVECTION Think…EARTH! (or oven) This is the process of heat rising and

cool air falling that we’ve talked about

CONVECTION Convection is the transfer of heat by the

actual movement of the warmed matter Liquids and gases Matter must be present Examples:

Heat a pot filled with pasta – rises and falls Heat from the center of the Earth rising –

Causing volcanoes and shifts in plates Ovens – heat rises and cools http://player.discoveryeducation.com/index.cf

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RADIATION Think….SUN! The sun’s rays provide us with heat,

maybe even a sunburn! But, it’s so far away we can’t actually touch it…

RADIATION Radiation is the transfer of energy through

electromagnetic waves Does not rely on any contact between

heat source and heated object Examples:

Sunburn from Sun’s raysHeat from campfire toasting marshmallow