Heat and
Temperature
Temperature
 The measure of the average kinetic
energy of all of the particles within
an object.
Temperature and Energy
 All particles are moving and have kinetic energy.
 We can not measure the KE of each molecule, so we
take an average of each one.
 Taking temperature is finding the average KE of
molecules.
 Feeling hot or cold is a rough estimate.
 It
is subjective.
Thermometer
 A device that measures temperature
Most
thermometers rely on the
expansion of either fluids or metal to
work.
Electric thermometers rely on a
change in current.
Temperature
Scales
Image/Text/Data from the University of
Illinois WW2010 Project
Celsius-Fahrenheit
Celsius – Fahrenheit Conversion
Equation
Fahrenheit temperature =
(9/5 X Celsius temperature) + 32.0
TF = 9/5t + 32.0
Fahrenheit-Celsius
Fahrenheit – Celsius Conversion
Equation
Celsius temperature =
5/9 (Fahrenheit temperature – 32.0)
T = 5/9(TF – 32.0)
Kelvin
 Based on Absolute
Zero (theoretical)
 The temperature at
which an object’s
energy is minimal
Celsius – Kelvin Conversion Equation
Kelvin temperature =
Celsius temperature + 273
T = t + 273
Relating Temperature to
Energy Transfer as Heat
 You feel hot and cold because of transfer of
energy. Molecules must come into contact
with one another.
 Hot = absorbing energy from object
 Cold = releasing energy from object
Heat
 The transfer of energy from the
particles of one object to those of
another object due to a temperature
difference between the two objects
Thermal Energy
Actions that Increase
Thermal Energy
Raise the temperature of the
object
Explanation
Thermal Energy
Actions that Increase
Thermal Energy
Explanation
Raise the temperature of the Increases the kinetic
object
energy of the atoms or
molecules
Thermal Energy
Actions that Increase
Thermal Energy
Raise the temperature of
the object
Pull atoms or molecules
that attract one another
farther apart
Explanation
Increases the kinetic
energy of the atoms or
molecules
Thermal Energy
Actions that Increase
Thermal Energy
Raise the temperature of
the object
Pull atoms or molecules
that attract one another
farther apart
Explanation
Increases the kinetic
energy of the atoms or
molecules
Increases the potential
energy of the atoms or
molecules
Thermal Energy
Actions that Increase
Thermal Energy
Raise the temperature of
the object
Pull atoms or molecules
that attract one another
farther apart
Add mass to the object,
without changing its
temperature
Explanation
Increases the kinetic
energy of the atoms or
molecules
Increases the potential
energy of the atoms or
molecules
Thermal Energy
Actions that Increase
Thermal Energy
Raise the temperature of
the object
Pull atoms or molecules
that attract one another
farther apart
Add mass to the object,
without changing its
temperature
Explanation
Increases the kinetic
energy of the atoms or
molecules
Increases the potential
energy of the atoms or
molecules
More molecules at the
same level of energy
means more total energy
in the object.
Thermal Energy Equation
Q = m ΔT C
 Q = change in thermal energy (J)
 m = mass (kg)
 ΔT = change in temperature (˚C)
 C = specific heat (J/kg ˚C)
Problem Plug and Chug
Q = 0.5 kg • 60 ˚C • 800 J/kg ˚C
mass
x change of temp x specific heat
Q = 24,000 J