Although not all graduate students will teach in the classroom, all will use teaching skills in some aspects of their work. Graduate students can participate in activities that will prove useful in later teaching situations. They can prepare audio-visual materials or design and conduct experiments and demonstrations in the laboratory. Carefully selected and well-prepared graduate students can give lecture or laboratory presentations; however, care must be taken not to detract from the quality and continuity of the course from the standpoint of students who are enrolled for credit (and are paying for the course).