Conduction Convection & Radiation

Conduction Conduction is the transfer of thermal energy by collisions between the particles that make up the matter Particles must be in contact for conduction to occur The particles in contact MUST have different amounts of thermal energy

What is happening? High Energy particles collide with the Low Energy particles and directly transfer thermal energy. High Energy Low Energy

Example: Conduction transfers thermal energy to the end of the spoon as particles with more kinetic energy transfer energy to particles with less kinetic energy High Energy Low Energy Low Energy High Energy

Conduction The best conductors of thermal energy are metals This is why cooking materials are made out of metal Silver, copper and aluminum are among the best conductors

Convection Convection is the transfer of energy in a fluid by the movements of warmer and cooler fluid *Fluids must flow = liquids and gases

Convection

Convection on Earth Convection currents drive our weather Warmer (moist) air from the equator rises As this air rises, it cools in temperature and loses moisture Cooler (drier) air sinks down toward the ground Temperature of falling air increases as it sinks

Radiation Radiation is the transfer of energy by electromagnetic waves such as light or microwaves These waves travel through space even when matter is not present

Radiation Energy transferred by radiation is called radiant energy When you stand near a fire, radiation transfers energy from the fire and increases the thermal energy of your body

Radiation When radiation strikes a material it can absorb, reflect or transmit some energy This depends on the type of matter Thermal energy increases when a material absorbs radiant energy