temperature heat thermal energy

							Temperature, Heat and Thermal Energy
           What is Temperature?
   Particles of matter are in constant motion. This
    motion relates directly to the state of matter of
    the object (solids, liquids, or gases).


   Temperature affects how fast these particles
    move. The higher the temperature the faster the
    particles move. Moving particles possess
    kinetic energy.


   Temperature is defined at the average kinetic
    energy of the particles of an object.
Temperatures You
Need to Know:
  It is important to
 know the freezing
 and boiling points
        of water.
    Absolute zero                         oF   oC     oK
     refers to the
   temperature at         Water boils     212 100 373
       which all
                       Room Temperature   72   23     296
    movement of
   particles in an       Water Freezes    32    0     273
 object would stop!
                         Absolute Zero    -460 -273   0
    Thermal Energy and Temperature:
   Thermal Energy is the sum total of all of the
    energy of the particles of an object.
   Thermal energy and temperature are related
    though DIFFERENT.
   Temperature is the average kinetic energy of the
    particles of an object.
   Thermal energy is the total amount of energy of
    the particles of an object.
       ?? A bathtub full of water at 100F has more thermal
        energy than a thimble of water at 100F.
                           WHY????
Thermal Energy and Temperature:

                More water at the same
                 temperature = more
                   thermal energy!!




       Less water at same
        temperature = less
          thermal energy
Thermal Energy

    Which beaker of water has more
     thermal energy?


               80ºC              80ºC

         A                 B
                                      400 mL

                 200 mL
Thermal Energy - Answer
    Which beaker of water has more
     thermal energy?
        B because it has more MASS!!!


                   80ºC                  80ºC

            A                   B
                                           400 mL

                     200 mL
     Let’s Sum Temperature and Thermal
                Energy Up!
   Temperature is a measure of the average heat
    or thermal energy of the particles in a
    substance. Since it is an average measurement,
    it does not depend on the number of particles in
    an object. It only depends on the amount of
    Movement of those particles.
   THERMAL ENERGY is the amount of Movement
    the particles have. Increasing the amount of
    movement of the particles can increase the
    amount of heat it has therefore it will increase
    its temperature!!
    Then, what is HEAT?
   Heat is really the amount of thermal energy
    being passed from one object to another.

   Heat travels in a specific direction!!! ALWAYS
    from the warmer object to the cooler object.




   So, if heat is the amount of thermal energy, then
    the amount of heat an object has tells me how
    much kinetic energy the object has.
       Ice = cold temp and very little movement = very little
        heat/kinetic energy/thermal energy of its particles!!!
       Fire = high temp, a lot of movement, so high
        heat/kinetic/thermal energy!!!
Heat Transfer

    Why does A feel hot and B feel cold?


                 80ºC                 10ºC

          A                    B
Heat Transfer - Answer

    Why does A feel hot and B feel cold?
         Heat flows from A to your hand = hot.
         Heat flows from your hand to B = cold.

                     80ºC                     10ºC

             A                       B
So…
When we take a temperature
 we are seeing how much
 heat has been transferred in
 to an object. Based on the
 amount of heat, the particles
 will move a lot or a little.

Movement can keep the
 temperature constant or
 increase/decrease it.
 Therefore, temperature is
 directly related to heat and
 heat is the amount of
 thermal energy passed to an
 object!!!
                   Heat is always transferred
Heat Transfer       from hot to cold.


                   Insulators slow the
                    transfer of heat/energy.


                   Conductors allow the
                    transfer of heat, like
                    metals.


                   Heat is transferred by
                    conduction, convection,
                    and radiation.
   How is Thermal Energy Transferred?
3 MUST KNOWS!!!!!
Conduction – through direct contact!

Convection – through a gas or liquid , moves in currents!

Radiation – electromagnetic waves through
empty space, no medium required!
    Conduction
   Heat is transferred
    due to objects
    touching each other or
    through collisions.
   Occurs best through
    solids.
   Heat continues to be
    transferred until both
    objects reach the
    same temperature,
    called a thermal
    equilibrium.
Conduction
   When you heat a metal strip at one end, the heat
   travels to the other end.




   As you heat the metal, the particles vibrate, these
   vibrations make the adjacent particles vibrate, and so on
   and so on, the vibrations are passed along the metal and
   so is the heat. We call this? Conduction
Metals are different


  The outer e______ of metal atoms
              lectrons
  drift, and are free to move.

                                       When the metal is
                                       heated, this ‘sea of
                                                        inetic
                                       electrons’ gain k_____
                                       energy and transfer it
                                       throughout the metal.


                                      ood       lastic
                Insulators, such as w___ and p____, do not
                have this ‘sea of electrons’ which is why they
                do not conduct heat as well as metals.
Why does metal feel colder than wood, if they are
both at the same temperature?


   Metal is a conductor, wood is an insulator. Metal
   conducts the heat away from your hands. Wood
   does not conduct the heat away from your hands as
   well as the metal, so the wood feels warmer than
   the metal.
    Convection
   Transfer of heat
    through a liquid or gas
    through moving
    currents, called
    convection currents.
   The cause of wind and
    weather.
Convection

  What happens to the particles in a liquid or a
  gas when you heat them?


                      The particles spread out and
                          become less dense.




                        What is a fluid? A liquid or gas.

                         This effects fluid movement.
Fluid movement


                               ense
                 Cooler, more d____, fluids
                 sink through w_____, less
                               armer
                 dense fluids.

                 In effect, warmer liquids and
                 gases r___ up.
                        ise

                                           ink
                 Cooler liquids and gases s___.
Water movement

               Cools at the   Convection
                 surface       current



   Cooler                                  Hot water
 water sinks                                 rises
Why is it windy at the seaside?
Radiation
   Transfer of heat
    through
    electromagnetic
    radiation waves. Like
    from the sun, a fire or
    a light bulb.
   Transferred in all
    directions.
   No contact required!
   Dark or dull objects
    absorb more than light
    or shiny objects do.
Emission experiment

   Four containers were filled with warm water. Which
   container would have the warmest water after ten minutes?

                Dull metal                  Shiny black




  Shiny metal                Dull black

       shiny metal
 The __________ container would be the warmest after ten
 minutes because its shiny surface reflects heat radiation back
                                                    _______
                                         dull black
 into the container so less is lost. The ________ container
                                                  emitting
 would be the coolest because it is the best at _______ heat
 radiation.
Absorption experiment

Four containers were placed equidistant from a heat lamp. Which
container would have the warmest water after ten minutes?

                Dull metal                  Shiny black




  Shiny metal                 Dull black


         dull black
  The __________ container would be the warmest after ten
                                            radiation
  minutes because its surface absorbs heat _______ the best.
       shiny metal
  The _________ container would be the coolest because it is
  the poorest at __________ heat radiation.
                   absorbing
    Heat Transfer
    Summed UP!

   Heat:
        Thermal energy that
         flows from a warmer
         material to a cooler
         material and,
   Like work, heat is...
        a transfer of energy!
        Can be measured in
         Joules (J).