Okumus, Samet/0000-0001-5905-196X; Hollebrands, Karen/0000-0001-8266-1467WOS: 000504919800010This case study addresses how middle school students use gestures concomitant with verbal expressions to relate the features of two- and three-dimensional objects. Eight students (five girls and three boys) participated in the study. Students (12-14 years old) used hands-on manipulatives and a dynamic geometry program, Cabri 3D, to form three-dimensional objects from two-dimensional figures using extrusion or spinning. Students used gestures to describe missing elements of three-dimensional objects that were not represented in the tools. During the extrusion activities, students' pointwise and objectwise gestures provided a visual representation for the edges and lateral faces/surfaces of three-dimensional objects. During the spinning activities, some students had difficulty relating the features of two- and three-dimensional objects. Some students employed gestures accompanied by verbal expressions to demonstrate the circular and continuous motion of spinning as well as to represent the lateral surfaces of three-dimensional objects. These gestures stood for the missing (unrepresented) elements of three-dimensional objects in hands-on manipulatives and Cabri 3D when students formed three-dimensional objects using an extrusion or spinning method.Direct For Education and Human ResourcesNational Science Foundation (NSF)NSF- Directorate for Education & Human Resources (EHR) [1712280] Funding Source: National Science Foundatio
