THERMAL ENERGY TRANSFER

Thermal Energy Transfer

Thermal Energy can be transferred by three methodsConductionConvectionRadiation

Conduction Conduction is the transfer of thermal

energy by contact between particles of matter from a high temperature to a low temperature

Heat moves faster through solids and liquidsThis is because the particles are

closer together

Convection Convection is the transfer of thermal energy

by the partcles of a fluidFluids are liquids and gasesCurrents transfer heat from high

temperature to low temperatureAs a fluid heats up it expands and

becomes less denseThis heated fluid will then rise above fluid

of a lower temperature

Radiation Radiation is the transfer of energy by

electromagnetic wavesIt can travel through space where

there is no matterThis is radiant energy

Radiation

Materials can absorb, reflect, or transmit radiationDark colors absorb radiationLight colors reflect radiation

Radiation can pass through the particles that make up solids liquids and gases

Insulators

An insulator is a substance that heat flows slowly through

They will have a high specific heat Gases make good insulators because

they do not conduct heat well

THERMODYNAMICS

Using Heat On of the most basic ways of using heat

is to heat your home Most homes used a forced air system

that pumps warm air into a room and heat the room by convection

Radiators

Older buildings may use radiators A radiator uses steam to heat rooms by

convection

Thermodynamics

You can increase the thermal energy of an object with out adding heat

Thermodynamics is the study of the relationship between thermal energy, heat, and work

1st Law of Thermodynamics The increase in thermal energy of a

system equals the work done on the system plus the heat transferred to the system

2nd Law of Thermodynamics It is impossible for heat to flow from a

cool object to a warmer object unless work is done.

If you hold ice in your hand, heat flows from you to the ice cube

Engines

Heat can be converted into work A heat engine is a device that turns heat

into work It is impossible to make an engine that

completely converts heat into work This is because it will violate the second

law of thermodynamics