As well as lectures and tutorials, courses in the experimental sciences include a laboratory component, which gives the student the opportunity to gain direct "hands-on" experience of the phenomena of interest. e be er prepared a student is, the be er the use that can be made of time in the laboratory. It is vital that the best use of the expensive resources (experimental apparatus and personal academic help) be made in the limited time that they are available (2-3 hours). Students have always been encouraged to read the experimental notes before a ending the laboratory, and to encourage them to do so a "pretest" must be submi ed before they enter the laboratory. Even a er successfully completing the pre-test, however, students are o en at a loss to know exactly what to do when confronted with unfamiliar equipment, and much demonstrator time can be spent on repeatedly explaining the same simple starting procedures.