Exploring the mathematical model of the thumbaround motion by geogebra

Abstract

The article explores the mathematical model of the thumbaround motion by GeoGebra. GeoGebra is a dynamic mathematics software whose fundamental idea is producing multiple representations. GeoGebra can provide both algebraic and geometric representations synchronously through its algebra and geometry windows. In modeling the situation, we represent the cross-section of the thumb as a circle and the pencil as a line segment. The length of the pencil, the radius of the thumb, and the point on the pencil where it initially meets the thumb, are each changeable via sliders in the GeoGebra construction. An animation simulates the thumbaround action, in which the pencil rotates around the thumb. During the animation, the tip point of the segment that represents the pencil traces a curve.