Themes > Science > Physics > Cryogenics > Temperature > Temperature and Temperature Scales
 
  • Temperature is a measure of the motion of the individual atoms and molecules in a gas, liquid, or solid.

       

    • If an object has a high temperature its constituents are moving around energetically.

         

      • In a gas at high temperature the individual gas molecules are moving about independently at high speeds.
      • In a solid at high temperature the individual atoms of the solid are vibrating energetically in place.
    • The converse is true for a "cold" object.

         

      • In a gas at low temperature the individual gas molecules are moving about sluggishly.
    • There is an absolute zero temperature at which the motions of atoms and molecules practically stop.
  • A thermometer can be calibrated in a variety of arbitrary ways.

       

    • The Farhenheit scale sets zero at the freezing point of a salt-water mixture and 100 at body temperature -- not very scientific.

         

      • Absolute zero is -459 degrees in this system.
      • Room temperature is 70 degrees.
    • The Celsius (or centigrade) scale sets zero at the freezing point of pure water and 100 at the boiling point of pure water -- a bit more scientific.

         

      • Absolute zero is -273 degrees in the Celsius system.
      • Room temperature is 20 degrees
    • The Kelvin scale sets zero at the absolute zero of temperature and uses degrees that are the same size as in the Celsius system.

         

      • Absolute zero is 0 degrees in the Kelvin system.
      • Room temperature is 293 degrees
    • Astronomers and Physicists widely use the Kelvin temperature scale.


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