A worksheet is a page (or two) of tasks, distributed to each student to do either in class or at home, intended to be written on, and usually taken in by the teacher to be checked. Teacher-made tests can be seen as a specific kind of worksheet. 'Workcards are made in sets, each card offering a different, fairly short task. They are not written on: a student does one card, writing answers on a separate piece of paper or in a notebook, and then exchanges it for another, working through as many of the set as there is time for. Answers are often available for self-checking at some central location in the room, or on the back of the card itself.
Workcards are permanent and re-usable; worksheets are disposable - though of course further copies can be made. Workcards take more effort and time to produce, but they are also more attractive to look at and work on (colours and cut-out pictures can be used), and more individualized: students have a choice as to which cards they do, and in which order; and the range of tasks available can be much more varied. In fact, the workcard lesson is a rudimentary self-access session, and can be developed into a fully individualized programme by varying the number and type of tasks provided.