School children are required to study 5 days a week in school and then go home and do the homework.
Their performance, progress and competence is directly contingent upon these factors.
At college a student is more self-sufficient.
There is less classroom time and more self-directed study.
At university the student must attend the required number of lectures and then flesh out the study all by themselves.
As with school, there will be assignments and examinations to confirm comprehension and understanding.