Integrated View at the MTCS Course Organization: The Case of Recursion - Guide to Teaching Computer Science: An Activity-Based Approach - page 216

mental construction process of the concept of recursion 3 (Levy and Lapidot
2000 ).
• The students are also asked (a) to expand their classified sets by adding new
instances to each set, (b) to give a title to each set, and (c) suggest a title for
the whole page. The specific instructions are presented in Table 12.1 .
Table 12.1 Classification task
Worksheet: Classification task
Levy and Lapidot ( 2000 ) present a page with 15 phenomena (see appendix A of the
article). Choose your own criteria and categorize/classify these images into sets. An
image can belong to several sets. For example, image X can be included in set A
because it satisfies the 'a criterion' and to be included in set B because it also satisfies
the “b criterion.”
Add a new instance (not from the given page) to each set.
Give a title to each set.
Give a title to the whole page.
• Stage B: Class discussion
• After the teams worked on their classification, each team shares its catego-
rization with the rest of the class. This sharing process can be performed in
different forms. Here are several options: (1) a group presents the instances
of a specific set and the whole class should guess their classification cri-
terion, (2) a group presents its additional new instance to one of the sets
and the class should guess which of the other instances presented in the
worksheet belong to this set, (3) a group presents their title for one of the
sets and the whole class should guess which instances belong to that set,
and (4) a group presents 3-5 instances that cannot belong to one of its sets
and the class should guess what the criterion was according to which items
were included in that set (i.e., what was the classification criterion).
• During the discussion, the instructor should encourage a reflective discourse,
offer generalizations, and present the formal terminology with respect to
recursion related to the mentioned constructs. Learners, in general, and the
prospective computer science teachers in the MTCS course, in particular,
are often exposed in this discussion to new concepts and to different ideas
and perspectives offered by other groups. This exposure, in turn, encourages
their reconsideration of their previous perspective at recursion.
• The instructor summarizes the main concepts related to recursion that
have been introduced in this discussion, and encapsulates them under the
umbrella of one concept—recursion. As a preparation for the next stages of
3 This observation is not surprising since the phenomena were chosen very carefully so that they
represent recursive structures and entities.