What is the difference between a journal written by an eyewitness to an event and a play written about the same event

Examine the causes, course, and consequences of united states westward expansion and its growing diplomatic assertiveness (war of 1812, convention of 1818, adams-onis treaty, missouri compromise, monroe doctrine, trail of tears, texas annexation, manifest destiny, oregon territory, mexican american war/mexican cession, california gold rush, compromise of 1850, kansas nebraska act, gadsden purchase).