Transfer of Thermal Energy : Transfer of Thermal Energy
Thermal Energy : Thermal Energy
Thermal Energy : Thermal Energy Thermal Energy - How quickly or slowly molecules move.
The more thermal energy an object has, the faster its molecules move.
The less thermal energy an object has, the slower its molecules move.
The flow of thermal energy is called Heat.
Heat moves from warm things to cool things.
-Hands on Desks
Thermal Energy (cont.) : Thermal Energy (cont.) Objects expand as heat is added. Why?
Molecules move farther apart because thermal energy makes them move more quickly.
-Bimetallic Strip
How is Heat Transferred? : How is Heat Transferred? Heat can flow from one place to another in three ways:
Conduction
Convection
Radiation
Conduction : Conduction
Conduction : Conduction Conduction – Passage of heat energy from molecule to molecule in an object.
Conductor – An object that conducts heat well.
Examples: Copper, Aluminum, Steel
Insulator – An object that does not conduct heat well.
Examples: Wood, Plastic, Rubber
-Demonstration-
Convection : Convection
Convection : Convection Convection – The transfer of heat energy by molecules moving together throughout a container.
Warm fluid rises
Cool fluid sinks
Moving heated fluid creates a cycle of warm and cool fluid. This is called a convection current.
-Demonstration-
Radiation : Radiation
Radiation : Radiation Radiation – The transfer of heat energy on electromagnetic waves.
Examples: UV rays, Infrared
Things that radiate heat:
Fire, the Sun, Heat Lamps, Radiators
Dark colors absorb radiant heat better than light colors.