Then, as now, the purpose was to supplement a college education with hands-on experience. Accredited cooperative education programs exist in over 120 schools around the country. You rotate work and school semesters through the whole year, including summers, so that you can focus on one endeavor at a time. For the semesters you work, you report to work 40 hours a week, usually around 7 or 8 each morning. For the semesters of school, you enroll in a full-time load of classes, and generally do not work.
Some employers prefer co-ops to work on a parallel plan.
This means working an average of 20 hours per week and completing a part-time load of classes, usually a minimum of 9 hours, every semester. The employer determines whether the position is alternating or parallel based on their needs. You work at a job directly related to your major, that is supervised by professionals in your intended field. You will work with people who will teach you the ropes of your profession. Work assignments are progressive.