There are two versions of this activity:
As a whole class activity, the instructor cuts a pumpkin in order to produce a small volume element \(d\tau\), interspersing their work with a sequence of small whiteboard questions. This version of the activity is described here.
As a small group activity, students are given pineapple rounds and pumpkin wedges to explore area and volume elements in cylindrical and spherical coordinate systems. In this version of the activity, the fruit is distributed to the students with appropriate children's pumpkin cutting equipment, as part of activities Vector Differential--Curvilinear, Scalar Surface and Volume Elements, or Vector Surface and Volume Elements.
As described here, this activity has been done as a whole class activity where students answer a series of small whiteboard questions (SWBQ) as the instructor makes cuts in a pumpkin to construct a volume element in spherical coordinates. This activity can be done as a small group activity by giving pieces of pineapple slices and pumpkins, together with appropriate children's pumpkin cutting tools, while students are doing Scalar Surface and Volume Elements or Vector Surface and Volume Elements.
If done as an instructor led whole class activity, the following provides a structure for the activity done in spherical coordinates using a pumpkin.