CONVECTION: THE TRANSFER OF THERMAL ENERGY BY THE MOVEMENT OF THE PARTICLES FROM ONE PART OF A MATERIAL TO ANOTHER; TRANSFER OF THERMAL ENERGY IN A FLUID (LIQUID OR GAS)

Heat Transfer

Heat Transfer : The movement of heat energy from an area of higher temperature to an area of lower temperature

The three types of heat transfer…

1. Conduction

2. Radiation

3. Convection

Conduction

Conduction : heat is transferred by DIRECT CONTACT (Touch)

Ex/ You burn your hand on a hot pot

Ex/ Your bare feet lose heat to a cold tile floor

Ex/ Hot soup transfers heat to the spoon

.

Radiation

Radiation - the transfer of heat through space by electromagnetic waves (No touching!!)

Ex/ A fire warming your hands

Ex/ The sun heating the Earth

Convection Convection is heat transfer WITHIN a fluid

(liquid or gas) by the movement of the particles

Ex/ Boiling waterEx/ A fire heating the room

How does Convection work?

• The particles closest to the heat source gain energy, move apart, become less dense, and rise up.

• The particles then lose energy, move together, become more dense, and sink back down.

• This repeats – forming a CONVECTION CURRENT

Convection and the Mantle• Heat Source – Core• Heated rock from the asthenosphere rises up

towards the crust• Cooler rock near the crust is more dense, and

is pulled back into the mantle