What is the difference between long period and short period
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The short run refers to a period of time short enough so that the amounts of at least one or more of the factors of production used by the firm cannot be changed. ... By the long run we mean a period of time long enough so that the amounts of all factors of production used by the firm can be changed.

Evaporation: this is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas). water vapour droplets join together to make clouds! condensation: this is when water vapour in the air cools down and turns back into liquid water.