What work should I set my students if I am absent?

You should try to set appropriate and relevant work for all the students in your classes.  Take into account the range of abilities. Make sure that the resources are available.  Avoid practical activities since there is no guarantee that a specialist teacher will cover your lesson(s), and this would also be for health and safety reasons.  Avoid copying out exercises,and passive activities where student do not engage in thinking.   The work should engage students in meaningful activities, and be of a high standard. Independent learning activities are encouraged,. Ensure that the relevant resources are available. You should assume that a specialist teacher will not be placed to cover your lesson(s).