There are two types of processes (or reactions): spontaneous and non-spontaneous. Spontaneous changes, also called natural processes, proceed when left to themselves, and in the absence of any attempt to drive them in reverse.
When does fall start in Alabama? Officially, the first day of fall is the Autumnal Equinox on September 23. However, the end of summer is considered to be the day after Labor Day, which is the last summer hâ¦oliday. Autumn leaves in the deep south usually begin in late October to early November. 4 people found this useful.
Seasons are fundamental to how we understand the climate and the environment, but for hundreds of years academics have argued that their specialist field is the one which defines official start of autumn. In meteorological terms autumn begins on September 1, as each season is defined as a three-month period. Astronomers base the date of the seasons upon celestial events, in this case the autumnal equinox, when night and day are roughly equal length.