Waldorf schools set great store by practicals, which begin in the upper-middle school and continue all the way through the high school. They normally last two to three weeks, so that young people really have a chance to connect with theme, work and people concerned. The challenge represented by each practical is gauged according to the particular age-group. They vary from school to school. The aim is always that the students do not simply observe what is going on, but actually participate in the specific work-situation. More exact insights into natural processes and food production are gained in the forestry, agriculture or ecology practical. First experience of the world of work comes through the craft or industry practical (called in some quarters the work experience practical). In the social practical, the students have a chance to become acquainted with the nature of social work by helping in various institutions with the care of children, the handicapped, the sick or the aged. Compared to others, the land surveying practical in grade 10 occupies a unique position. Besides the professional and physical challenges to be faced, the social side of these practicals always plays an important role in the lives of the young people concerned. The work outside school is prepared and reviewed in class discussions and closely supervised by teachers. Very often each class will give a report of their experiences to the school community. Documentation is also compiled in the form of diaries, journals or portfolios. According to the aim of the particular practical and the external circumstances concerned, it can take the form of a class trip, or be carried out on an individual or small-group basis.