The term "apprentice" is defined in sec. 3077 of the Shelley-Maloney Apprentice Labor Standards Act of 1939 as: "... a person at least 16 years of age who has entered into a written agreement, in this chapter called an 'apprentice agreement,' with an employer or his agent, an association of employers, or an organization of employees, or a joint committee representing both, which apprentice agreement provides for not less than two thousand hours of reasonably continuous employment for such person and for his participation in an approved program of training through employment and through education in related and supplemental trainings." The training of apprentices is an educational program, the primary purpose of which is to develop an adequate supply of skilled craftsmen to meet the needs of industry for such workers. The apprentice is a full-time worker who learns his craft on the job while working for an employer who provides the necessary supervisory staff and journeymen workers to instruct the apprentice in the manipulative skills of the craft. In addition, the apprentice learns the technical knowledge related to his craft in school classes provided for this purpose.