Heat Transfer

The Transfer of Heat
energy – the ability to make things move or change
thermal energy – how heat moves from one object to
conductor – a material through which heat can move easily
*examples – stainless steel, iron, silver, copper, aluminum
insulator – a material that heat does not move through easily
*examples – rubber, brick, wood
How Heat Transfers
 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
 Heat transfers in three ways
o conduction
o convection
o radiation
 the transfer of heat between things that are touching
 objects are in direct contact with each other
 occurs when a substance is heated –
o particles gain energy and vibrate more.
o these particles bump into nearby particles and transfer
some of their energy to them
 metal (iron, silver, copper, stainless steel) = good conductor
 Example of Conduction
o heating a pot of water on an electric stove – heat moves
from the hot surface of the stove to the metal of the pot
that is touching the stove
 the transfer of heat by the movement of the heated parts of a
liquid or gas
 the transfer of heat by the actual movement of the warmed
 occurs when warmer areas of liquid or gas rise to cooler areas in
the liquid or gas
o Examples of Convection
 water boiling in a pan
 heat is passed by movements called convection currents
 molecules in liquids and gases move apart when they are
 convection current - movement of heated molecules to cooler
 the transfer of energy by electromagnetic waves
 electromagnetic waves can transfer energy through matter and
also through empty space
 The sun is the earth’s main source of electromagnetic waves
 Examples of radiation
o heat from the sun warming your face
o heat from an open fire
o heat from a light bulb
kinetic energy – energy that is in motion
potential energy – possible or stored energy