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.
astronomically it begins with the autumnal equinox around september 23 in the northern hemisphere and march 21 in the southern hemisphere so in meteorology for the northern hemisphere spring begins by convention on march 1 summer on june 1 autumn on september 1 and winter on december 1stronomically it begins with the autumnal equinox around september 23 in the northern hemisphere and march 21 in the southern hemisphere so in meteorology for the northern hemisphere spring begins by convention on march 1 summer on june 1 autumn on september 1 and winter on december 1