HEAT,WORK,AND TEMPERATURE

Heatis thermal energy in transit. It cannot be accumulated or stored.

When thermal energy flows from a hot body to a cold one (the reverse never occurs without the expenditure of work), it should be called heat. However, when flow ceases as a result of temperature equilibrium, the thermal energy gained by the cold body should not be referred to as heat.

Work(W) is also a quantity in transit. It is a force acting through a

distance [equivalent to lifting a weight a distance (l) vertically:W =Fl].

Static energyis the capacity for doing work.

Temperatureexpresses the thermal energy level of a body. The

molecules of a body vibrate at very high frequency, but with an amplitude that increases with the thermal energy level of the material. The structural configurations called solid, liquid, and gas are states of matter. The two temperature scales in common use today are defined in terms of the transition of one of the mostcommon substances (water) from solid to liquid (freezing point) and from liquid to vapor (boiling point) at one atmosphere pressure. Celsius (1741) took the freezing point of water as 100° and the boiling point as 0°, and divided the scale between into 100 equal parts. Later the scale