Chapter 6
THERMAL ENERGY
Temperature and Heat
Temperature- the average amount of kinetic energy of an object’s atoms or molecules
Thermal Energy- The sum of the KE and PE of the molecules in an object
Heat is thermal energy that flows from higher temperature to lower temperature
o Changes in thermal energy can be by mass times change in temperature times specific heat.
Q = (m) (ΔT) (C)o Measured in Joules
Specific Heat- the amount of heat needed to raise the temperature of 1 kg of a material 1 degree C
C = ΔQ/(m ΔT)
Measured in Joules / (kg°C)
o Specific Heat is a physical property of a material
Transferring Thermal Energy
Conduction
Convection
Radiation
Conduction
The transfer of heat by direct contact.
conductor - a material that transmits energy readily
example: metals
insulator - a material that does not transmit energy readily
Occurs in every state of matter, but solids are better conductors because of the closeness of the atoms.
ConvectionThe transfer of heat by the actual motion of a fluid (liquid or gas) in the form of currents.
won't work in solids…Why??? molecules are locked in place
Two types – natural and forced.
RadiationHeat transfer by electro-magnetic waves.
Light, UV rays, X-rays, & infrared rays.
Does not require matter.
Conduction/Convection/Radiation
Analogies
Conduction- passing a note from student to student
Convection- a student gets out of her/his seat and walks over and delivers the note to its recipient
Radiation- the first student tosses the note to its recipient