As we observe that Primary 6 students have difficulties finding cross sections of various 3D solids, we designed a lesson using 3D Printing Pens to support students’ visualisation through hands-on, inquiry-based learning. Students were given different regular solids, such as prisms, cylinders, and pyramids. Then, they were invited to use the 3D Printing Pens to draw along the surface of the objects in order to inquire what various cross sections of the solids would look like. For example, they would draw along the outline of the cross section of a cylinder and then detach their drawings from the solids to investigate what shapes the cross sections took on (see figures below)
Students developed strong spatial sense through this activity. Moreover, they could obtain the correct cross section of prisms and pyramids with high accuracy. The teachers involved in this experiment suggest that without a tool like 3D Printing Pens, students find it very difficult to visualise what various cross sections look like, especially for pyramid. After the lesson, we performed some task-based interviews and asked students not to use 3D Printing Pens when visualising cross sections. Even though they did not use the 3D Printing Pens, they produced gestures that imitate their drawing processes with 3D Printing Pens during the interviews. We conclude that the lesson activity with 3D Printing Pens supported the students with tools (i.e. gestures) for visualising cross sections of 3D solids.