World Journal of Educational Research
ISSN 2375-9771 (Print) ISSN 2333-5998 (Online)
Vol. 8, No. 5, 2021
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Original Paper
Developing Student-Teachers’ Understanding of Geometrical
Figures/Objects Using a Bicycle Rubber Tube
Emmanuel Deogratias1*
1
Department of Mathematics and Statistics, University of Dodoma, Dodoma, Tanzania
*
Emmanuel Deogratias, Department of Mathematics and Statistics, University of Dodoma, Dodoma,
Tanzania
Received: September 25, 2021,
doi:10.22158/wjer.v8n5p1
Accepted: October 18, 2021
Online Published: October 22, 2021
URL: http://dx.doi.org/10.22158/wjer.v8n5p1
Abstract
This paper addresses the ways that a bicycle rubber tube can be used to develop learners’
understanding of geometrical figures/objects. The use of a bicycle rubber tube is important because
student-teachers and in-service teachers can use the material to teach learners in schools to
understand various geometrical figures/objects. In doing so, geometrical figures and objects, metric,
and metric space are understood relationally. Using a bicycle rubber tube, it was found that various
geometrical figures and objects were formed, including rectangle, triangle, square, and pentagon. The
finding has implications in teaching geometrical figures/objects, including teachers can use a bicycle
rubber tube to develop learners’ understanding of a circle, rectangle, triangle, square, pentagon and
hexagon.
Keywords
geometrical figures/shapes, metric, topology, bicycle rubber tube
1. Introduction
This paper presents the learned activities on how an elastic rubber tube was used for forming various
geometrical figures/objects. In forming various geometrical figures, the concepts of metric and
topological spaces were found useful. This paper contributes to the use of real objects in forming
various geometrical shapes and figures, in this case a bicycle rubber tube. This is important for active
engagement of student-teachers with mathematical concepts and support intended learning.
This paper raises the questions in what ways is it different to teach and learn with a moldable shape that
returns to the original shape, compared to, say, a series of separate, rigid objects? As a student watches
a pentagon returns to a circular form, what learning affordances or enjoyments are there?
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World Journal of Educational Research
Vol. 8, No. 5, 2021
This paper is influenced by the work of Karssenberg (2014) on “learning geometry by designing
persian mosaics” (p. 43) on developing and implementing lesson plan in university mathematics
classrooms. Karssenberg designed mathematics lessons that students learned by acting while focusing
on their origin cultures in mathematics classrooms, which played a significant role in stimulating their
interest in learning mathematics as well as learning achievements. However, the lessons based on a
European context and focused on students in secondary schools. This paper presents the lesson focused
on African context, in particular post-colonial context such as in Tanzania while using a bicycle rubber
tube. The university student-teachers learned by doing in designing and forming geometrical
shapes/figures using real objects available in local environment. In doing so, Zaslavsky (1999) argues
that “students become aware of the role of mathematics in all societies. They realize that mathematical
practices arose out of people’s real needs and interests” (p. 318).
The design and formation of geometrical figures/shapes are originated in the history of mathematics
(Gerdes, 1998, 2010; Kartz, 1998). As such, the formation and design of geometrical figures/shapes
depend on three stages. First stage involves creativity by realizing the specific patterns that are
designed (Hogendijk, 2012). Second stage involves drawing the geometrical shapes/figures by
presenting the instructions showing how drawing process took place (Necipoglu, 1995). The last stage
involves scaling the constructed patterns of a drawing (Necipoglu, 1995).
2. The Didactical Approach: Learning by Doing
The design and formation of geometrical shapes and figures are based on the conceptual framework of
activity (Cole & Engestrom, 1993). Cole and Engestrom suggest using a mediational triangle by
expanding it to model any activity. In our lesson with student-teachers, a rubber tube was formulated in
the shape of a triangle and then was expanded to form other geometrical shapes including a circle,
triangle and pentagon.
3. Learning Mathematics by Doing in Forming and Designing Geometrical Figures/Shapes Using
a Bicycle Rubber Tube
In this example, learning by doing is used in a way that student-teachers focused on giving an
interesting project followed by presentations and discussions. The lesson was stimulating by making a
colorful geometrical shapes and figures using bicycle rubber tube. Student-teachers worked together in
a small group which reduced time needed to work on the activity per teacher.
A mediational triangle for student-teachers who participated in the lesson for forming geometrical
shapes/figures using a bicycle rubber tube involved the following aspects:
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Table 1. A Mediational Triangle for Forming Geometrical Figures/Shapes Using Bicycle Rubber
Tube
Aspects
Active Process
Subject
The student-teachers’ participation.
Tools
An elastic rubber tube (a bicycle rubber tube) of circumference 194 cm for
forming various geometrical shapes and figures, rubber bands for fixing points,
and tape measure for measuring various sides of the geometrical shapes
resulting from the bicycle rubber tube (circular elastic rubber).
Objects
To gain knowledge and skills in forming and designing geometrical figures
using tools available in their daily environment.
To collectively form and design geometrical figures by giving mathematical
analysis.
Extra rules
The teacher educator divides a class into small groups. The educator gives
instructions on how the project and presentations are assessed.
Communities
The
group
of
geometrical
formulators
and
designers
presents
(3
student-teachers). Other student teachers become audiences for the
presentations.
Division of labour
The teacher educator gives a project task to formulate and design geometrical
figures/shapes using a bicycle rubber tube followed by small group
presentations. The educator has power to assess the group presentations while
student-teachers own the class (power in practice).
Outcomes
Presentations and mathematical analysis of the formed and designed
geometrical shapes/ figures using a bicycle rubber tube. These demonstrate
the knowledge and skills gained by students on geometry, including
geometrical objects/figures, and construction.
4. Mathematical Tools
Before the student-teachers could form and design geometrical figures/shapes using a bicycle rubber
tube, they would need to become aware of metric and metric space, topology and topological space,
and geometrical shapes/figure. This is important because formation of geometrical shapes and figures
involves measurements and understanding the shapes of the materials so that we can form various
shapes from a bicycle rubber tube by stretching the material without destroying it.
4.1 Metric and Metric Space
Metric space refers to the space occupied by the distance function between two points in a given set
(Copson, 1968; Jain & Ahmad, 1999; Korner, 2015). The space occupied by the length of a ruler is an
example. Also, Singh (2019) defines metric space as let
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be a non-empty set. A metric on
is a
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such that the following conditions are satisfied for all
function
•
•
(positivity)
•
(symmetry)
•
(triangle inequality)
The set
value
together with a metric
is known as a metric space, the elements of
on a pair of points
refers to the distance between
and
are called points. The
.
Metric space is used in measuring the distance between two points. For example, the distance between
two points on a ruler, say P and Q is given by
which is always positive. The
distance between the two points on the ruler is symmetry. For instance, the distance from points
on the ruler is equal to the distance from
to
. That is,
to
(Korner, 2015; Singh,
2019; Sutherland, 2009).
Metric space can be used in choosing the shortest distance between two points. For instance, when
transforming a bicycle rubber tube into a triangle, let say
, it is found that the distance of one side
is always less or equal to the sum of two other sides.This demonstrates the triangular equality in the
triangle
such
all
that
Geometrically, this representation can be addressed as: In
any right-angled triangle, the length of a side is less than or equal to the sum of the length of the other two
sides (Singh, 2019; Sutherland, 2009).
4.2 Topology and Topological Space
A topology is a geometrical perspective of an object. It can be known as the deformation of a material
into different homeomorphic shapes without destroying the physical structure (or nature) of the
material. Such material can be bent, crumpled, stretched or even pulled (Kelly, 1995; Korner, 2015;
Munkres, 2000; Singh, 2019). In this context, we are going to employ an elastic material to
demonstrate topology.
The space occupied by a geometrical perspective of an object is called a topological space.
(Singh, 2019) defined a topological structure or simply a topology on set
subset of
as a collection of
;a
such that:
•
The intersection of two members of
•
The union of any collection of members of
•
The empty set
and entire set
is in
is in
are in
Topological spaces can be used to form different structures or shapes which are homeomorphic to each
other and can be used in different purposes (Bryant, 1994; Korner, 2015). For instance, a bicyle rubber
tube can be used to form various geometrical shapes without deforming it. The shapes that can be formed
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from the rubber band include a circle, rectangle, pentagon, and hexagon. The geometrical shapes formed
are topologically equivalent. Using the concept of topological space saves time, space as well as other
resources such as materials. For example, a carpenter may decide to design a table which can be used as
both a chair and bed whereby three items are homeomorphic to each other. Therefore, the concept of
topological spaces can be used in daily life to save time, cost and proper utilizatiozation of materials and
spaces.
Mathematically, we can define a homeomorphism between the two spaces Y and Z as a bijective
function
such that both
to be homeomorphic, denoted by
and
are continuous. In this case, two spaces
if there is a homomorphism
and
are said
(Singh, 2019).
5. The Student-Teachers Start Formulating and Designing Geometrical Figures
Two techniques were used in forming different geometrical figures and shapes using a bicycle rubber
tube.
•
Measurements: A tape measure to measure the lengths of geometrical shapes such as a circle,
triangle, rectangle and pentagon as a result of stretching a bicycle rubber tube.
•
Interpolation; we used variations of measurements to transform a circular rubber into different
shapes step by step which were homeomorphic to each other or simply topologically equivalent.
Various geometrical shapes were formed by using a bicycle rubber tube including a circle, triangle,
rectangle and pentagon. The new shapes so formed were measured their sides using a tape measure (see
Figure 1).
Figure 1. Measurements of the Geometrical Shapes Formed from A Circular Bicycle Tube
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The following steps were followed while transforming a circular bicycle tube into different geometrical
shapes.
Step 1: A bicycle rubber tube was stretched to form a triangle. Then, the rubber tube was transformed into
triangle by fixing it at two distinct points and stretching another point without cutting, tearing or gluing it.
circular rubber into triangle
Figure 2. Transforming a Circular Bicycle Tube into A Triangular Shape
Student-teachers analyzed that a circular rubber tube of length 194 cm was transformed into a triangular
shape of length 196 cm. The difference in lengths of the two geometrical shapes are a result of stretching
a bicycle rubber tube in the process of forming a triangular shape. Also, circular and triangular rubber
tubes so formed were homeomorphic to each other. These means the two geometrical shapes were
topologically equivalent.
Step 2: A formed triangle was stretched into a rectangle: A triangular rubber tube was fixed at two distinct
points and also stretched at two district points without cutting, tearing or gluing it.
Triangle into Rectangle
Figure 3. Transforming a Triangular Figure into a Rectangular Figure
Student-teacher analyzed that a triangular rubber tube of length 196 cm was transformed into a rectangle
of length 210 cm. The difference in lengths of the two geometrical shapes are a result of stretching a
bicycle rubber tube in the process of forming a rectangular shape. The shapes were topologically
equivalent.
Step 3: A formed rectangle was also stretched into a pentagon. A rectangular rubber tube obtained from
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step 2 was interpolated by fixing it at four distinct points and extended at one point which was different
from the four points without cutting, tearing or gluing it.
Rectangle into pentagon
Figure 4. Transforming A Rectangular Figure into A Pentagon
Student-teachers analyzed that a rectangular rubber tube of length 210 cm obtained from step 2 was
interpolated by fixing it at four distinct points and extended at one point which was different from the
four points without cutting, tearing or gluing it to form a pentagon of length 212 cm. The difference in
lengths of the two geometrical shapes are a result of stretching a bicycle rubber tube in the process of
forming the shape of a pentagon. It was found that the shape of the rectangular rubber tube and that of the
penton rubber tube were topologically equivalent.
Step 4: A formed pentagon was stretched into a circle. We needed to make a back change of drawing a
pentagon into a circle. Since the geometrical topological shapes were formed by fixing and stretching an
elastic bicycle rubber tube, then, on release the elastic material drew itself into a circle which we had as
our original material.
Pentagon stretched into circle
Figure 5. Transforming A Pentagon into A Circle
Student-teachers analyzed the process by focusing on the importance of transforming the shape of a
pentagon formed from the rectangular rubber tube (see step 3) into a circle. This transformation was
important to make a back change of drawing a pentagon of length 212cm into a circle of length 194cm.
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Since the topological shapes were operated by simply being fixed and stretched, then on release the
elastic material drew itself into a circle (original material). Also, the shape of a pentagon and that of a
circle were topologically equivalent.
6. Reflection on the Results
Reflection is presented based on the practical activities/ operational issues involved from the results
obtained in steps 1, 2, 3 and 4 during small group presentations. We noticed that all geometrical shapes
from steps 1 to 4 are homeomorphic figures describing the shapes of a circle, triangle, rectangle and
pentagon, are all made from circular rubber tube. This is to say, we can further manipulate the circular
rubber tube to form other geometries (shapes) which are also topological equivalent. Other geometrical
shapes include square, hexagon and octagon.
We also learned that the geometrical shapes formed from circular rubber tube after stretching and
transforming it, were topological equivalent. However, there were a slight difference in their metrics due
to stretching and compressing the rubber tube while forming various geometrical shapes.
These learning activities for student-teachers are quite different from what usually take place in their
university mathematics classes. These teachers usually work on group assignment on the activities.
However, the activities are not practical based. Also, these teachers work on the assigned activities while
they are outside the class. Because of this, teacher educator cannot know how the learning process
proceeds in small group discussions.
7. Concluding Thoughts
The use of a bicycle rubber tube in forming and designing geometrical figures/shapes in this way in this
paper is critical: student-teachers were motivated in learning and created interest of using the material
in teaching and learning situations to dilute the scarcity of teaching and learning aids/materials in
mathematics classrooms. For instance, a mathematics teacher while teaching geometry can use a
bicycle rubber tube in demonstrating the shapes of various polygons and how they are formed, instead
of drawing various polygon figures on the chalkboard/white board. In doing so, it helps in managing
time and spaces during teaching and learning process. Also, students learn by doing in small groups
followed by class discussions on how a bicycle rubber tube can be used in forming various geometrical
shapes. This identifies ways of reducing tensions among students while working on geometrical items.
We conclude with the issue of mathematics education by relating with cultural context. Our lesson was
potential for giving student-teachers power in practice while in mathematics classrooms. A
mathematics educator followed Karssenberg (2014)’ approach on non-western cultures in producing
mathematics and profiting everyone. In our class with student-teachers, it gave positive impacts in
teaching and learning geometrical figures/objects while using a moldable shape that returns to its
original shape.
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Acknowledgement
My acknowledgement goes to the student-teachers who participated in this study.
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