HEAT AND TEMPERATURE
  • Water coming out of a tap can be around 20C
  • Water coming out of a coffee pot can be around 90C
  • Water coming out of a refrigerator can be around 4C


    • If I asked you which of these is hot, you would say the coffee water at 90C.
    If I asked you which of these is cold, you'd say it was the fridge water at 4C.
    What about the tap water?

    CONCEPT 1:
    All of the three situations listed (coffee, fridge, and tap) describe water at a different TEMPERATURE.  Temperature is a human creation.  We made up temperature scales so we could have a way to describe things.

    What does temperature describe?
    Temperature describes how fast, on average, particles in a substance are moving.  The particles in the coffee are moving more quickly than the particles in the tap water.

    CONCEPT 2:
    The motion of the particles shows how much energy they have.  This energy is motion energy, and we call it HEAT.

    ARE HEAT AND TEMPERATURE THE SAME THING?
    NO!
    Imagine you are observing water coming out of a sink...
     

  • if you have only the hot turned on, you get high temperature water with a lot of heat energy
  • if you have only the cold turned on, you get low temperature water with less heat energy (but still has some energy, because you could cool it by putting it in the fridge!)


    • WHAT IF you turn them both on all the way?
     

  • Obviously, you get more water.
  • You get a higher temperature than the cold water alone.
  • You get a lower temperature than the hot water alone.
  • You get MORE HEAT.


    • CONCEPT 3:
    Many people get confused here because they have always thought that heat and temperature were the same thing.  Imagine you're in a bath tub and the water has fallen to a very chilly 23C.
    Look at these two bowls of water:

    Which of these two bowls would do a better job of heating your bath water?
    In this case, it is actually the colder one that will heat you up more!
    Why?
    Because there is a lot more water, there is more energy.  Sure the smaller and hotter water will heat you up somewhat, but it can only do so much.

    DO YOU GET IT?