In conventional schools, activities are chosen by the teacher and scheduled by the clock. Instead of being organized by the clock, Montessori activities are structured through the classroom environment, carefully prepared by the teacher. The teacher observes the children in the classroom then presents lessons to individuals or small groups, depending on the interest and readiness of individual children. Children are then free to repeat the hands-on activity during the long work period. Routine and ritual are determined by the activity instead of by a schedule so that the children have ample time to choose and complete activities, fostering their independence and confidence. Of course, this child-centered approach depends upon a strong classroom community that works at respecting boundaries that promote healthy individuals and a healthy group.