International Perspectives On The Teaching and Learning of Geometry in Secondary Schools Patricio Herbst Install Download
International Perspectives On The Teaching and Learning of Geometry in Secondary Schools Patricio Herbst Install Download
https://textbookfull.com/product/international-perspectives-on-
the-teaching-and-learning-of-geometry-in-secondary-schools-
patricio-herbst/
https://textbookfull.com/product/the-learning-and-teaching-of-
geometry-in-secondary-schools-a-modeling-perspective-1st-edition-
pat-herbst/
https://textbookfull.com/product/teaching-and-learning-secondary-
school-mathematics-canadian-perspectives-in-an-international-
context-ann-kajander/
https://textbookfull.com/product/international-handbook-of-
learning-teaching-and-leading-in-faith-based-schools-1st-edition-
judith-d-chapman/
https://textbookfull.com/product/miracle-of-education-the-
principles-and-practices-of-teaching-and-learning-in-finnish-
schools-2nd-edition-hannele-niemi/
Pedagogy for Technology Education in Secondary Schools
Research Informed Perspectives for Classroom Teachers
P. John Williams
https://textbookfull.com/product/pedagogy-for-technology-
education-in-secondary-schools-research-informed-perspectives-
for-classroom-teachers-p-john-williams/
https://textbookfull.com/product/critical-perspectives-on-
teaching-learning-and-leadership-enhancing-educational-outcomes-
mathew-a-white/
https://textbookfull.com/product/the-wiley-international-
handbook-of-history-teaching-and-learning-harris/
https://textbookfull.com/product/iterative-design-of-teaching-
learning-sequences-introducing-the-science-of-materials-in-
european-schools-1st-edition-dimitris-psillos/
https://textbookfull.com/product/learning-and-teaching-british-
values-policies-and-perspectives-on-british-identities-1st-
edition-sadia-habib-auth/
ICME-13 Monographs
Patricio Herbst
Ui Hock Cheah
Philippe R. Richard
Keith Jones Editors
International
Perspectives on
the Teaching and
Learning of Geometry
in Secondary Schools
ICME-13 Monographs
Series editor
Gabriele Kaiser, Faculty of Education, Didactics of Mathematics, Universität
Hamburg, Hamburg, Germany
Each volume in the series presents state-of-the art research on a particular topic in
mathematics education and reflects the international debate as broadly as possible,
while also incorporating insights into lesser-known areas of the discussion. Each
volume is based on the discussions and presentations during the ICME-13 Congress
and includes the best papers from one of the ICME-13 Topical Study Groups or
Discussion Groups.
Editors
International Perspectives
on the Teaching and Learning
of Geometry in Secondary
Schools
123
Editors
Patricio Herbst Philippe R. Richard
School of Education Département de didactique
University of Michigan Université de Montréal
Ann Arbor, MI Montreal, QC
USA Canada
This Springer imprint is published by the registered company Springer International Publishing AG
part of Springer Nature
The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland
Contents
v
vi Contents
Abstract This chapter introduces the book by providing an orientation to the field
of research and practice in the teaching and learning of secondary geometry. The
editors describe the chapters in the book in terms of how they contribute to address
questions asked in the field, outlining different reasons why prospective readers
might want to look into specific chapters.
This book is one of the outcomes of Topic Study Group 13 at the 13th International
Congress on Mathematical Education, which took place in Hamburg, Germany, in
the summer of 2016. Our Topic Study Group (TSG-13) concerned the teaching and
learning of secondary geometry and the chapters in this volume include revised
versions of most of the papers presented at the main meetings of the group. Also
included are a handful of the shorter papers associated with TSG-13 in the context
of short oral communications. In this brief introduction we orient the reader to these
papers by first providing an organizer of the focus of our study group.
The International Congress in Mathematics Education gathers researchers and
practitioners in mathematics education and pursues a goal of inclusiveness across
all sorts of boundaries. In particular, the boundaries between research and practice
P. Herbst (&)
University of Michigan, Ann Arbor, USA
e-mail: pgherbst@umich.edu
U. H. Cheah
Institut Pendidikan Guru Malaysia, Penang, Malaysia
e-mail: uhcrecsam1@gmail.com
K. Jones
University of Southampton, Southampton, UK
e-mail: d.k.jones@soton.ac.uk
P. R. Richard
Université de Montréal, Montréal, Canada
e-mail: philippe.r.richard@umontreal.ca
are often blurred in ICME and this surely applied to our Topic Study Group 13 in
ICME-13. Therefore, to orient the reader to the chapters in the book, it might be
useful to describe the territory or field of practice associated with the teaching and
learning of secondary geometry.
As we engage in such a description, we might benefit from using the metaphor of
map-making as a guiding principle. Borges’s short story On exactitude in science
uncovers the futility of expecting that a map be produced on a scale 1:1. Yet the
value of maps as containers of geographic knowledge and as resources for travelers
cannot be overemphasized, even if the existence of different kinds of projection
techniques reminds us that any map has limitations in what it affords its readers.
Different maps afford us different kinds of insight on the territory.
There is a constellation of practices that might be spotted as we look toward the
teaching and learning of geometry in secondary schools. At the center of this con-
stellation is the classroom practice of students and teacher transacting geometric
meanings. Near that center one can find the practice of textbook writing and materials
development for secondary geometry; one can also find the practice of preparing
teachers to teach secondary school geometry; and the individual practice of thinking
and problem solving that youngsters of secondary school age may engage in even
outside of school. But as we look closer, finer, relevant distinctions can be made.
The practice of teaching and learning geometry in classrooms admits of one set of
distinctions regarding the institutional location of those classrooms: American
secondary schools locate that practice in a single high school geometry course, while
geometry is integrated with other content areas in most other countries, and also
occurs outside of compulsory education, in other organized settings such as summer
camps. None of our papers inquires specifically on the institutional situatedness of
geometry instruction, though Kuzniak’s chapter recommends investigating whether
there is a place for the study of geometry in all educational systems, and uses a
contrast between work observed in Chile and in France as a way into his approach to
questioning the nature of geometric work. Other chapters present inquiries that seem
to rely on such situatedness. The chapter by Berendonk and Sauerwein, for example,
describes geometry experiences with novel content in the context of a summer
course for mathematically-inclined students, and the chapter by Herbst, Boileau, and
Gürsel examines how the instructional situations that are customary in the US high
school geometry course serve to frame a novel geometry task. Steeped into the
institutional location of the teaching and learning of geometry in high school in the
United States, Senk, Thompson, Chen, and Voogt examine outcomes of geometry
courses taught using the Geometry text from the University of Chicago School
Mathematics Program. Likewise Hunte’s chapter examines curricular variations
situated in the context of textbooks of different eras in Trinidad and Tobago.
Specific geometry content at stake in classroom instruction, as well as in teacher
development, textbook writing, and thinking and problem solving is discussed
implicitly or explicitly in all chapters. Several chapters focus on specific geometric
concepts: area of trapezoids (Manizade and Martinovic’s chapter), area of triangles
(Cheah’s chapter), properties of quadrilaterals (Herbst, Boileau, and Gürsel’s
chapter), polytopes (Berendonk and Sauerwein’s chapter), rotations (Battista and
1 International Perspectives on Secondary Geometry Education … 3
Manizade and Martinovic demonstrate how they use student work to elicit teachers’
responses that allow them to assess what they know about specific geometric topics.
In contrast, Smith uses the MKT-G test (Herbst & Kosko, 2014) to measure the
amount of mathematical knowledge for teaching geometry of practicing and pre-
service teachers across the domains hypothesized by Ball, Thames, and Phelps
(2008). Additionally, Smith uses a questionnaire to access self-reported pedagogical
practices of her participants. Also, the chapter by Villella and his colleagues from
Grupo CEDE describes how teachers’ knowledge of geometry can be developed
through experiences framed using ideas from the theory of geometric working
spaces introduced earlier in Kuzniak’s chapter.
As the chapters address those practices, they do so from multiple perspectives
that cover the range between practitioner and researcher. The chapters by
Berendonk and Sauerwein and by Steketee and Scher illustrate the work of
developing curriculum materials for the teaching of geometry. The development of
assessments for teachers is showcased in the paper by Manizade and Martinovic,
while the development of games for students is showcased in the paper by Luz and
Soldano. The chapter by Cheah illustrates the work of engaging teachers in pro-
fessional development using lesson study, while the chapter by Villella et al.
describes activities used in other professional development activities. The chapters
by Maresch, by Senk et al., and by Smith are based, at least in part, on the use of
tests. The observation of actual classroom interaction is present in a number of
papers including, in particular, Chinnappan et al.’s chapter and Herbst et al.’s
chapter. We come back in the conclusion to some methodological aspects of the
work presented.
The various ways in which we map the practices of teaching and learning ge-
ometry in secondary school highlight many connections and distinctions among the
chapters in the book. Surely more can be found through reading and with such
purpose we invite the reader to dig in. The book represents a collaborative effort
among editors in four different countries (Canada, Malaysia, the United Kingdom,
and the United States) working alongside 40 authors, affiliated with 25 different
institutions from 14 different countries. These authors put together 21 chapters. In
such representation of diversity, this book not only represents diverse perspectives on
the practice of teaching and learning geometry in secondary schools, but also rep-
resents the diversity among the individuals who attended ICME-13. May this diverse
offering of ideas inspire the reader to become a contributor to ICME in the future.
References
Ball, D. L., Thames, M. H., & Phelps, G. (2008). Content knowledge for teaching what makes it
special? Journal of Teacher Education, 59(5), 389–407.
Herbst, P., & Kosko, K. W. (2014). Mathematical knowledge for teaching and its specificity to
high school geometry instruction. In J. Lo, K. R. Leatham, & L. R. Van Zoest (Eds.), Research
trends in mathematics teacher education (pp. 23–46). New York: Springer.
Chapter 2
Thinking About the Teaching
of Geometry Through the Lens
of the Theory of Geometric Working
Spaces
Alain Kuzniak
Keywords Construction Discursive dimension Geometric work
Geometric paradigms Geometric working space Instrumental dimension
Proof Register of representation Reasoning Semiotic dimension
Visualization
2.1 Introduction
The purpose of this essay is not to give a general and critical overview of research
done in the domain of geometry education. First, this type of survey already exists
(e.g., the recent and very interesting ICME-13 survey team report, Sinclair et al.,
2016), and secondly, because given the extension of this field, such surveys are
generally partial and, sometimes, even biased. Indeed, geometry is taught from
kindergarten to university in many countries, and students engage with it in
very different ways, eventually depending on their professional orientation
A. Kuzniak (&)
Laboratoire de Didactique André Revuz, Paris Diderot University, Paris, France
e-mail: kuzniak@math.univ-paris-diderot.fr
1
The French curriculum is set by the central government and official instructions are published in
the Journal Officiel. Our short summary on the evolution of the teaching of geometric transfor-
mations is based on this material.
8 A. Kuzniak
not really know well and from which they do not master even elementary tech-
niques. Surprising situations occur when, as in CERME in 2011, researchers from
countries where geometric transformations were just re-introduced in elementary
school were wondering whether it is possible to teach them to young students.
French researchers could only report that it was possible, but that transformations
were just removed from their curriculum.
Before dealing with this question, we need to ask ourselves if there is a place for
geometry, as a discipline clearly identified, in all education systems. Indeed, one of
the main issues of the report on geometry done by the Royal British Society (2001)
was to foster the reappearance of the term geometry in the British curriculum. Prior
to this, the study of geometry had been hidden under the heading “shape, space and
measure.” Similar disappearance is apparent in the PISA assessment, in which
geometry topics are covered up by the designation “space and shape”.
These changes of vocabulary are not harmless as they are not only changes in
vocabulary; rather, they reveal different choices about the nature of the geometry
taught in school. The choices imply either a focus on objects close to reality or on
objects already idealized. The decisions on the type of intended geometry relate to
different conceptions of its role in the education of students, and also, more gen-
erally, on the citizen’s position in society. In the French National Assembly, during
the middle of the nineteenth century, a strong controversy about the nature of the
geometry taught in school pitted the supporters of a geometry oriented towards
immediate applications to the world of work against the defenders of a more
abstract geometry oriented to the training of reasoning (Houdement & Kuzniak,
1999). During the second half of the twentieth century, a third more formal and
modernist approach, based on linear algebra, was briefly, but with great force,
added to the previous two (Gispert, 2002). Thus, over the long term and in a single
country,2 the nature of geometry taught fluctuated widely and issues and goals have
changed dramatically depending on decisions often more ideological and political
than scientific. Observations of the choices made nowadays in various countries
reveal irreconcilable approaches that seem to resurrect the debate mentioned above.
2
This conflicting approach on the teaching of geometry is not typically French. In the US, similar
tensions albeit among four different conceptions exist too (Gonzalez & Herbst, 2006) based on
formal, utilitarian, mathematical or intuitive arguments.
2 Thinking About the Teaching of Geometry Through the Lens … 9
Anybody that has had the opportunity to observe classroom instruction in a country
other than his or her own must have noticed differences in style that can hardly be
accounted to individual differences. The researchers affiliated with the TIMSS
sub-study on teaching practices in six countries noticed such differences in style,
and they used the notion of “characteristic pedagogical flow” to account for
recurrent and typical styles they observed (Cogan & Schmidt, 1999).
To me, this variety of styles appears when reading Herbst’s historical study
(2002) on two-column proofs in the USA. This way of writing proofs is similar to
nothing existing now in France though it is reminiscent of an old fashioned way
used to write solutions of problems in primary school where operations have to be
separated from explanations of reasoning. Another case of cultural shock appears
too when reading Clanché’s and Sarrazy’s (2002) observation of a first-grade
mathematics lesson in a Kanaka primary school (New Caledonia). This time, the
teacher cannot easily assess the degree of understanding of his students for whom
customary respect for the elders forbids their expression of doubts and reservations
in public and thus they never ask some complementary explanation to the teacher.
The analysis of the classroom session allows the authors to claim that the rela-
tionship between mathematics teaching and students’ everyday life should be
analyzed as rupture or obstacle more than as continuity or facilitation.
Let us consider some different styles through an observation made during a
comparative study on the teaching of geometry in Chile and France (Guzman &
Kuzniak, 2006). Various exercises were given to high school pre-service teachers in
Strasbourg, France and in Valparaiso, Chile. As an illustration, we show two stu-
dents’ work using exactly the same solution method but presenting it in radically
different ways. Both are characteristic of what is expected by their teachers.
In Chile, results are given on a coded drawing and the reasoning used is not
explicitly given in writing. By contrast, in France, a very long and detailed text is
written and no assertion, not even the most trivial, is omitted. This point is clearly
apparent in Fig. 2.1 even if Spanish and French texts are not translated.
Observations of Chilean classrooms show that what is written on the blackboard
during a session is often similar to the student’s written production and only oral
justifications are provided, while in France all arguments have to be written
(Guzman & Kuzniak, 2006). Knipping (2008) also shows differences in the use of
the blackboard and in articulation between the written and the oral in France and
Germany. More generally, Knipping (2008) shows that argumentation and proof3
are not equivalent in both countries; rather they give birth to different ways of
developing geometric work in the same grade.
How can we account for these differences in “style” avoiding, if possible, any
hierarchical comparison based on the idea that one approach is fundamentally better
3
In this essay, I mean proof more generally than mathematical or formal proof and different ways
of arguing or validating are considered.
10 A. Kuzniak
than the other? In the following, I will propose a way to explore these differences
based on the use of geometric paradigms and the theoretical and methodological
model of Geometric Working Spaces (GWS).
Houdement and Kuzniak (1999) introduced the notion of geometric paradigms into
the field of didactics of geometry to account for the differences in styles in geometry
education. To bring out geometric paradigms, three perspectives are used: episte-
mological, historical, and didactical. The assemblage of those perspectives led to
the identification of three paradigms usually named Geometry I (or Natural
Geometry), Geometry II (or Natural Axiomatic Geometry), and Geometry III (or
Formal Axiomatic Geometry). These paradigms—and this is an original feature of
the approach—are not organized in a hierarchy, making one more advanced than
another. Rather, their scopes of work are different and the choice of a path for
solving a problem depends on the purpose of the problem and the solver’s
paradigm.
The paradigm called Geometry I is concerned by the world of practice with
technology. In this geometry, valid assertions are generated using arguments based
upon perception, experiment, and deduction. There is high resemblance between
model and reality and any argument is allowed to justify an assertion and to
convince the audience. Indeed, dynamic and experimental proofs are acceptable in
Geometry I. It appears in line with a conception of mathematics as a toolkit to foster
business and economic activities in which geometry provides tools to solve prob-
lems in everyday life.
2 Thinking About the Teaching of Geometry Through the Lens … 11
The paradigm called Geometry II, whose archetype is classic Euclidean geom-
etry, is built on a model that approaches reality without being fused with it. Once
the axioms are set up, proofs have to be developed within the system of axioms to
be valid. The system of axioms may be left incomplete as the axiomatic process is
dynamic and has modeling at its core.
Both geometries, I and II, have close links to the real world, albeit in varying
ways. In particular, they differ with regard to the type of validation, the nature of
figure (unique and specific in Geometry I, general and definition-based in Geometry
II) and by their work guidelines. To these two Geometries, it is necessary to add
Geometry III, which is usually not present in compulsory schooling, but which is
the implicit reference of mathematics teachers who are trained in advanced math-
ematics. In Geometry III, the system of axioms itself is disconnected from reality,
but central. The system is complete and unconcerned with any possible applications
to the real world. The connection with space is broken and this geometry is more
concerned with logical problems (Kuzniak & Rauscher, 2011).
The model of GWS4 was introduced in order to describe and understand the
complexity of geometric work in which students and teachers are effectively
engaged during class sessions. The abstract space thus conceived refers to a
structure organized in a way that allows the analysis of the geometric activity of
individuals who are solving geometric problems. In the case of school mathematics,
these individuals are generally not experts but students, some experienced and
others beginners. The model articulates the epistemological and cognitive aspects of
geometric work in two metaphoric planes, the one of epistemological nature, in
close relationship with mathematical content of the studied area, and the other of
cognitive nature, related to the thinking of individuals solving mathematical tasks.
This complex organization is generally summarized using the two diagrams shown
in Figs. 2.1 and 2.2 (for details, see Kuzniak & Richard, 2014; Kuzniak, Tanguay,
& Elia, 2016):
Three components in interaction are characterized for the purpose of describing
the work in its epistemological dimension, organized according to purely mathe-
matical criteria: a set of concrete and tangible objects, the term representamen is
used to summarize this component; a set of artifacts such as drawing instruments or
software; a theoretical system of reference based on definitions, properties and
theorems.
The cognitive plane of the GWS model is centered on the subject, considered as
a cognitive subject. In close relation to the components of the epistemological level,
4
An extension of this model to the whole of mathematical work has been developed under the
name of Mathematical Working Space (MWS).
12 A. Kuzniak
precise study and definition of the nature and dynamics of these planes during the
solving of mathematical problems remains a central concern for a deeper under-
standing of the GWS model (Kuzniak, Tanguay, & Elia, 2016).
A GWS exists only through its users, current or potential. Its constitution
depends on the way users combine the cognitive and epistemological planes and
their components for solving geometric problems. It also depends on the cognitive
abilities of a particular user, expert or beginner in geometry. The make-up of a
GWS will vary with the education system (the reference GWS), the school cir-
cumstances (the suitable GWS) and the practitioners (personal GWS).
The framework makes it possible to question in a didactic and scientific—non
ideological—way the teaching and learning of geometry.
What is the geometry aimed at by education systems? What is the selected
paradigm? Does this paradigm get selected or does it emerge from practice in
schooling conditions? How do the different paradigms relate to each other?
Moreover, the nature and composition of the suitable GWS is to be questioned:
What artifacts are used? On which theoretical reference is the implemented geo-
metric work really grounded? Which problems are used as exemplars to lead stu-
dents in geometric work?
In the following, I develop two examples showing the possibilities offered by the
framework to deal with the above questions. I refer the interested reader to various
papers using the framework and its extensions, and, specially, the ZDM
Mathematics Education special issue on Mathematical Working Spaces in
schooling (Kuzniak, Tanguay, & Elia, 2016).
To show what a suitable GWS guided by Geometry I is, I use the findings from a
comparative study on the teaching of geometry in France and Chile quoted above
(Guzman & Kuzniak, 2006). Education in Chile is divided into elementary school
(Básica) till Grade 8 and secondary school (Media) till Grade 12. From 1998 on, the
teaching of mathematics has abandoned the focus on abstract ideas which was in
place before and turned into a more concrete and empirical approach. As of today,
the reference GWS is guided by Geometry I. To illustrate this and point out some
differences between France and Chile, let us consider the following exercise taken
from a Grade 10 textbook (Mare Nostrum, 2003).
14 A. Kuzniak
Students starting the chapter on similarity have to solve the following problem,
whose solution is given later in the same chapter:
Alfonso is just coming from a journey in the precordillera where he saw a field with a
quadrilateral shape which interested his family. He wants to estimate its area. For that,
during his journey, he measured, successively, the four sides of the field and he found them
to measure approximately: 300 m, 900 m, 610 m, 440 m. Yet, he does not know how to
find the area.
Working with your classmates, could you help Alfonso and determine the area of the field?
(Mare Nostrum, 2003, p. 92)
As four dimensions are not sufficient to ensure the uniqueness of the quadri-
lateral, the exercise is then completed by the following hint:
We can tell you that, when you were working, Alfonso explained the problem to his friend
Rayen and she asked him to take another measure of the field: the length of a diagonal.
Alfonso has come back with the datum: 630 m.
Has it been done right? Could we help him now, though we could not do it before? (ibid.)
The proof suggested in the book begins with a classical decomposition of the
figure in triangles based on the indications given by the authors. But the more
surprising for a French reader is yet to come: The authors ask students to measure
the missing height directly on the drawing. This way of doing geometry is strictly
forbidden at the comparable level of education in France.
How can we compute the area now? Well, we determine the scale of the drawing, we
measure the indicated height and we obtain the area of each triangle (by multiplying each
length of a base by half of the corresponding height). (ibid.)
In this example, geometric work is done on a sheet of paper and with the scaling
procedures, instruments for drawing and measuring, and a formula for calculating
the area of a triangle. In this first GWS, which I call the measuring GWS, splitting a
drawing of the field into two triangles and measuring altitudes makes it possible to
answer the question in a practical way. In that case, geometric work is clearly
supported by Geometry I and goes back and forth between the real world and a
drawing, which is a schematic depiction of the actual field. Measurement on the
drawing affords the missing data. The activity is logically ended by a calculation
with approximation, which relates to the possibility of measuring accepted in
Geometry I but not Geometry II.
A second GWS, the calculation GWS, supported by Geometry II is possible and
exists in France where the so-called Heron’s formula makes it possible to calculate
the area of a triangle knowing the length of its sides without drawing or mea-
surement. The two GWS share a common general strategy: splitting into two tri-
angles. But they do not share the other means of action, the justifications of these
actions, and the resulting geometric work.
In the example, the first two modeling spaces do not necessarily organize
themselves in a hierarchy where the mathematical model would have preeminence.
The GWS supported by Geometry I allows the problem to be satisfactorily solved
with a limited theoretical apparatus. The GWS supported on Geometry II avoids
2 Thinking About the Teaching of Geometry Through the Lens … 15
drawing and measuring and therefore its accuracy is not limited by the measure-
ment on a reduced scale or the imprecisions of the drawing. The procedure in this
GWS allows automation, for example by way of a program on a calculator. The
measuring GWS favors the use of instruments and therefore their associated
geneses, while the calculation GWS fosters the use of symbolic signs (semiotic
genesis). In both spaces, discursive genesis may be called upon to justify the
procedure used but in a different way, which changes the epistemological nature of
proof.5
To illustrate the interest of the GWS model and develop the question of the
completeness of geometric work, we will refer to a classroom session (Nechache,
2014) dedicated to the use of the intercept theorem6 (in French, le théorème de
Thalès, or in German Strahlensatz) in France at Grade 9 where the Geometry II
paradigm is favored by the curriculum. In this session, a restricted use of the
mathematical tool, the theorem, leads to a mathematical work that can be often
deemed incomplete. Nechache’s study (2014) helps to clarify some discrepancies
that often arise between the mathematical work produced by the students and the
work expected by the teachers. Our analysis is supported by the GWS model, which
enables highlighting the dynamic of geometric work through the various planes
determined by the model (Fig. 2.3).
In French education, from the 1980s, the use of the intercept theorem has been
gradually restricted to two typical Thales’ configurations: one named “triangle” and
the other “butterfly” (Figs. 2.4 and 2.5).
During the session observed by Nechache (2014), the teacher asks the students
to solve an exercise, taken from the textbook (Brault et al., 2012, p. 311), with nine
multiple choice questions having three alternative answers. Two figures corre-
sponding to Thales’ “butterfly” configuration are associated with the statement of
the problem.
The nine tasks can be characterized as simple, requiring a few abilities: deter-
mine reduction ratios, check equal ratios, and calculate the lengths of triangle sides.
The last four questions relate to the converse and contrapositive form of the
intercept theorem by referring this time to the second figure (Fig. 2.6b) to identify
the correct parallelism properties. In the textbook, the exercise is designed to train
students to identify key figures associated with the intercept theorem and master
routinized techniques. The cognitive activity is essentially based on visual and
5
See Footnote 3.
6
Also known in English as “basic proportionality theorem;” see https://en.wikipedia.org/wiki/
Intercept_theorem.
16 A. Kuzniak
which involve solely the semiotic dimension. The mathematical work is confined to
the [Sem-Ins] plane by using the butterfly diagram associated with Thales’ theorem
as a semiotic tool. The analysis of the entire session allows us to check that
students’ mathematical work is also confined and closed on the semiotic axis.
The teacher draws the first figure freehand on the blackboard. Before giving the
solution to the first question, he urges students to remember methods related to the
intercept theorem, which had been studied in an earlier lesson when the theorem
was introduced. The solution of the exercise is temporarily postponed in favor of a
work exclusively concerned with the theoretical referential in the suitable GWS
based on Geometry II that the teacher wants to implement. Later, a student reads the
question and gives the correct answer. The teacher agrees and asks him to justify
the answer. This demand of justification is new and is not part of the initial
problem: The student and all classmates remain silent. The teacher reads the
question again and addresses the students:
Teacher: When we tell you that a triangle is a reduction of another one, does
this not remind you of any property? No theorem? Well that’s a pity, we just
saw it 5 minutes ago. So, which theorem has to be applied when we have
such a configuration?
Faced with the remarkable silence of these students who, at this level of
schooling, only know two theorems (the Pythagorean and intercept theorems), and
given that the intercept theorem has just been the subject of an insistent reminder,
the teacher comes back again to the figure drawn on the blackboard by commenting
on it, then he proceeds to checking each of the conditions required to apply the
intercept theorem. He favors the discursive axis in the GWS model by changing the
nature of the task: a justification of the result is requested and needs to be based on a
theoretical tool. The mathematical work has changed and is now in the [Sem-Dis]
plane. The teacher starts by checking the trivial alignment of the points and the fact
that straight lines are transversals (secants in French).
Teacher: Are you sure? Do you have what is needed? How are the points
supposed to be?
Students: Aligned.
18 A. Kuzniak
Fig. 2.7 Work done by students versus work expected by the teacher
2 Thinking About the Teaching of Geometry Through the Lens … 19
The observation of this geometry session shows that students’ work is exclu-
sively located in the semiotic dimension favored by the textbook’s suitable GWS
and not expected in the suitable GWS implemented by the teacher. Hence, a
misunderstanding emerges between the work the students do and the work the
teacher expects: The misunderstanding relates to the change of validation in what
counts as proof. Indeed, no discourse of proof is expected in the textbook, but the
teacher does expect proof to be connected to the discourse in the suitable GWS.
Both students and teacher carry out their work diligently, but they do not do the
same geometric work and this work is incomplete because it is confined to only one
or two dimensions instead of all three dimensions of the GWS model.
have constructed with their compass, and others negate its existence by using the
triangle inequality and calculation.
The tension between precise and exact constructions has been renewed with the
appearance of dynamic geometry software (DGS). As Straesser (2002) suggested,
we need to think more about the nature of the geometry embedded in tools, and
reconsider the traditional opposition between practical and theoretical aspects of
geometry. Software stretches boundaries of graphic precision, and finally, ends by
convincing users of the validity of their results. Proof work does not remain simply
formal, and forms of argumentation are enriched by experiments, which give new
meaning to the classic epistemological distinction between iconic and non-iconic
reasoning. The first closely depends on diagram and its construction and relates to
the [Sem-Ins] plane and the second tends to be based on a discursive dimension
slightly guided by some semiotic aspects [Dis-Sem].
How do the semiotic, instrumental, and discursive geneses relate to each other,
and specifically how does the use of new instruments interact with semiotic and
discursive geneses in transforming discovery and validation methods? And how can
students’ geometric work be structured in a rich and powerful way? This is one of
the issues that the GWS model seeks to describe through the notion of complete
geometric work Kuzniak, Nechache, and Drouhard (2016a) which supposes a
genuine relationship between the epistemological and cognitive planes and artic-
ulation of a rich diversity between the different geneses and vertical planes of the
GWS model. The aim is not only to observe and describe existing activities but also
to develop some tasks and implement them in classroom for integrating the three
dimensions of the model into a complete understanding of geometric work
according to the perspective expected by teachers and that geometric paradigms
help to precise.
References
Boero, P. (2016). Some reflections on ecology of didactic researches and theories: The case of
France and Italy. In B. Hodgson, A. Kuzniak, & J. B. Lagrange (Eds.), The didactics of
mathematics: Approaches and issues (pp. 26–31). Cham: Springer.
Brault, R., Cipolin, M. C., Cuq, S., Daro, I., Ferrero, C., Marfaing, I., et al. (2012). Phare
Mathématiques 3e. Paris: Hachette.
Brousseau, G. (1986). Fondements et méthodes de la didactique des mathématiques. Recherches
en didactique des mathématiques, 7(2), 33–115.
Brousseau, G. (1987). L’enseignement de la géométrie en tant que modèle de l’espace. In G.
Brousseau (Ed.), Théorisation des phénomènes d’enseignement des Mathématiques. Thèse
d’état Université de Bordeaux (pp. 447–481). Bordeaux, France.
Clanché, P., & Sarrazy, B. (2002). Approche anthropodidactique de l’enseignement d’une
structure additive dans un cours préparatoire Kanak. Recherches en Didactique des
Mathématiques, 22(1), 7–30.
Cogan, L. S., & Schmidt W. H. (1999). An examination of instructional practices in six countries.
In G. Kaiser, E. Luna, & I. Huntley (Eds.), International comparisons in mathematics (pp. 68–
85). London: Education Falmer Press.
2 Thinking About the Teaching of Geometry Through the Lens … 21
Keywords 4-Polytopes Analogy Beliefs Constructional Empiricism
Four-dimensional Geometry Hypercube Induction Mental object
Platonic solids Reasoning by analogy Subject matter didactics
Workshop
Consider the following task: Show that the graph of a quadratic function is a curve
whose points are at equal distance from a fixed point and a fixed line.
“How to accomplish this task? I know. I open my dynamic geometry software
program and let it plot the graph of some quadratic function. Fortunately, there is
also a button that creates, by specifying a point and a line, the curve whose points
are at equal distance from them. So, I have a second curve on my screen; and, by
dragging the specified point and line, I can manage to put that new curve right on
top of the old one. Thus, indeed, both curves are exactly the same. QED.”
If someone actually solved the above task in the described way, he or she would
be convinced that both constructions yield the same curve. Thus, it would be
S. Berendonk
University of Duisburg-Essen, Essen, Germany
e-mail: stephan.berendonk@uni-due.de
M. Sauerwein (&)
University of Bonn, Bonn, Germany
e-mail: sauerwein@math.uni-bonn.de
^£r^,^^^
BIOGRAPHICAL SKETCHES. . 1101 C. W. GuTELU-s, editor
niul publisher of the Public Press, was Ijorn in Mifflinburg, Union
county, Pennsylvania, November 4, 1S:57, son of Israel and Sarah
Gutelius. The father was bom in ]snrchased in 1884 the general
store of William T. Forsyth at Northumberland and continued the
business until 188(1 In LSS-") he was appointed postmaster at
Northumberland and served in that office until IN'.M). He was
married in ISdri to Alice Gulick, by whom he has four children:
Charles G. ; \\ii\Wv L. : Jennie C, and J. " Howard. He served as
chief burgess of Northumberland for three successive years, and is a
Democrat in politics and a member of the Lutheran church. S. M. G.
Wenck, pharmacist, was born in the borough of Northumberland,
September 24, 1830, son of George and Elizabeth (Pardoe) Wenck,
of German and Quaker ancestry, respectively. He received an
ordinary education, and in 18o5 established his 2)resent business at
McEwensville, this county, where he remained until 1880; he then
removed his stock to Northumberland, where he has built up a large
trade. He was married in 1855 to Christiana Kauffman, by whom he
has three children: William G. ; Maggie, wife of Morton McFarland,
and Edgar S. Mr. Wenck is a member of the Lutheran church. James
Dieffenbacher was born in a part of Northumberland (now Montour)
county, Pennsylvania, May 31, ISOlJ, son of Conrad Diett'enbacher, a
native of Montgomery county, this State, and a grand.son of Conrad
Dief62
1102 HISTORY OF XORTHUMBEHLAND COUNTY. fenbaclier,
who was horn in Germany and settled and died on the farm where
our subject now resides. Our subject learned the carpenter trade,
which he followed forty years. He settled in Northumberland in 1831,
and was married in 1S3S to Nancy Goston, who died in 1842, the
mother of one child, James G. He was again married to Maria
Hunsicker. He was a justice of the peace twenty-two years and a
school director twenty years. Jacob M.A.TTHi.is, merchant, was born
iu York county, Pennsylvania, September 20, 1828, sou of John and
Elizabeth (Growl) Matthias, natives of York and Lancaster counties,
respectively. They moved to Daujihin county, Pennsylvania, where
both died. They were members of the Lutheran church. Jacob
Matthias was reared in York county, and attended the local schools;
he has been engaged in various occupations, such as boating,
driving stage, and railroading. In 1860 he removed to
Northumberland county and established his present business. In
1850 he married Susan Van Dyke, daughter of Israel Gross, of
Snyder county. Their children, by adoption, are: Mary Guistwelt, wife
of Harry Frey, of Cumberland county; Susan Gross, wife of Frank
Shilmer, of Northumberland, and Bertha Newman. Mr. Matthias and
wife are members of the Lutheran church; in politics he is a
Republican, and has served as overseer of the poor sixteen years.
Cyrus Broi'se. merchant, was born in that part of Union county which
is now Snyder county, Pennsylvania, October 15, 1840, son of Peter
and Amelia (Moore) Brouse, both natives of that county, and farmers
by occupation. They were members of the Lutheran church. The
mother died in 1887, and the father in 1889. They reared five
children, four of whom an^ living:Cyrus; Margaret, Mrs. E. I. Snyder,
of Lewisburg, Pennsylvania; Mary E., Mrs. Abel Johnson, of Union
county, and Franklin, of Sunbury. The subject of this sketch was
educated at the township schools and at Freeburg Academy. In
September, 1802, he came to Northumberland, and first engaged as
clerk for William T. Forsyth, with whom he remained until June,
1803; he then engaged with M. H. Taggart, and was subsequently in
the employ of Reuben Johnson, Colt & Todd, and others. April 1,
1888, he established his present business. In 18*54 he married
Esther J., daughter of John Johnson, of Point township, by whom he
has five children: Reuben; Franklin C, who married Sarah Dull, of
Lewisburg; Thomas; Williard, and Earl M. Politically Mr. Brouse is a
Republican, and has served as councilman and burgess of
Northumberland; he is a member of the K. of P. of Northumberland.
He and family are members of the Methodist Episcopal church, in
which he holds the office of recording steward. W1LLI.A.M B. Stoner,
physician and surgeon, was born at Westminster, Carroll county.
Maryland, October 2('), 1845. He received his education at a
collegiate institute at that place, now known as the Western
Maryland College, also received four years' instruction under
Professor Beggs, now of Belfast, Ireland, and graduated from the
Edinburgh University. After com
BIOGRAPHICAL SKETCHES. 1103 pleting his education he
read medicine with Dr. William Taylor, of Gettysburg, Pennsylvania,
was graduated from the Philadelphia University' of Medicine and
Surp^ery in ISfiC), and began practicing in Hummelstowu, Dauphin
county, where he remained until ISTI. From there he removed to
Georgetown. Northumberland county, and in IST:^ to
Northumberland, where he has since enjoyed an extensive practice.
His father, George W. Stoner, was a native of Dauphin county. He
married Mary A. Sullivan, and settled in Carroll county. Maryland,
where he engaged in farming and still resides. They reared ten
children, seven of whom are living: William B. : Georo-e W., of
Baltimore. Maryland; Annie, wife of John C. Eckenrode, of
Westminster, Maryland: Sarah S.. wife of Martin Babylon, of
Westminster; Leah S., wife of William C. Robinson, of Littlestown,
Pennsylvania; James M.. of Baltimore, and Maggie. Doctor Stoner is
a member of Eureka Lodge, F.
1104 HISTORY OF NORTHUMBERLAND COUNTY.
(Farnsworth) Reed. His father wa.s born in IT'JO in Shamokiu
township, where his father had settled, and where he lived and died.
After his marriage he located in Rush township, but in 1833 moved
back to Shamokin townshij). He was a Whig in politics, and a deacon
in the Baptist church for many years. He died in Shamokin township
in LSoU, and his wife in 1857. They reared seven children, all
deceased except Farnsworth and Sarah, Mrs. William Depew, of
Riverside. The subject of our sketch attended the schools of Rush
and Shamokin townships. In 1843 he married Rosanna, daughter of
David Miller, of Shamokin township, and has since resided in
Shamokin, Augusta, and Point townships, settling on his present
farm in the spring of 180G. His family consists of nine children: S.
O.. of Suiibury; Maria Elizabeth, Mrs. Charles P. Seasholtz, of
Northiuuberland; Clarissa A., Mrs. George W. Vandevender. of Snyder
county: Jacob A., a merchant of Winfield, Pennsylvania; Sarah L.,
Mrs. Thomas J. Tandelbing, of Packer's island; Laura D., Mrs. Charles
M. Park, of Kingston. Peimsylvania; Harriet I., Mrs. James B. Leslier,
of Nebraska: Elmer E.. of Point township, and George M., of Iowa.
Mr. Reed is an active memlier of the Republican party, and has
served in various township otKcps. He is a deacon in the Baptist
churcli of Xorthiimberland. Geoiuie M. Ditzler, farmer, was born in
Tnrbut township. Ncjnhumberland county, Penusylvauia. January -
">. ISl'.t, son of Jacob and Sarah l Overpeck) Ditzler. He was
educated in the pul)lie schools and learned the trade of tinsmith,
which occupation he followed for ten years and has since been
farming. In 1S74 he was married to Isadore M., daughter of Stephen
Bittenbender. one of the early settlers of Shamokin, by whom he has
one child. William. He is a member of the Masonic lodge of
Northumberland, the chapter of Danville, and also of the Danville
commandery. He is a Republican, and a member of the Lutheran
church. He settled upju his present farm in 187.") and is bringing it
to a high state of cultivation. H.\KEisoN C. Kase, farmer, was Ijorn in
Rush township, Northumberland county, Pennsylvania, April 2U,
1N44. His father, Charles Kase. was also born in Rush township. His
grandfather, John Kase, was a native of England, who came to
America as a young man, married Eleanor Dewitt, a native of New
Jersey, and was among the early settlers of Rush to^^Tiship. He
and his wife were members of the Presbyterian church for many
years. They retired from farming and moved to Ely.sburg, where
both died. They reared eight children, four of whom are living:
Charles, of Riverside: Catharine, Mrs. George West, of Danville;
Clinton, a farmer of Montour county, and James, of Danville. Charles
Kase, the father of our subject, was engaged in farming in Rush
township until he retired and moved to Riverside, where he now
resides. He is a stockholder in the Danville Bridge Company. Mt.
Carmel Bank, and Danville nail factory. His wife died, Augnst '25,
1880. Thev reared four children; Oscar S., of Riverside; Harrison C. ;
BIOGRAPHICAL SKETCHES. 1105 Hannah Ellen, deceased,
and John Wilson. The subject of this sketch was reared in Eush
township and .^lucated in the township schools and Dan\ille
Academy. In 1SG3 he went as a substitute for his father in Company
H, One Hundred and Seventy-second Penn.sylvania Volunteers, and
served nine months, when he re-enlisted in Company A, Sixteenth
Pennsylvania Cavalry, and served one year; since then he has been
engaged in farming. February 2, 1870, he married Maranda Ellen,
daughter of Robert and Bethiah (Banghart) Davidison, natives of
New Jersey and settlers of Montour county, bv, whom he has three
children: Cora May; Eleanor Gertrude, and Bertha Ellen M. Politically
Mr. Kase is a Eepublican, and has served in the various township
otKces; he is a member of Goodrich Post. G. A. R.. and of the
Presbyterian church of Danville. Robert Cukky McWilliams, farmer,
was born in Mooresburg. Montour county, Pennsylvania, February
20, 1845, son of John and Margaret (Caldwell) McWilliams, of the
same county, and of Scotch-Irish extraction. He received his
education at the juiblic schools, and at academies at Milhille,
Pennsylvania, and Newark, New Jersey. His business career has been
principally that of a farmer, and he came to this county in 1872. In
October, ]87(), he married Louisa V. Reighard, daughter of Dr. Jacob
Reighard. of Juniata county, this State. To this union have been born
six children: Margaret Caldwell; Lucinda AVagner: Amanda Belle;
Jenette June; Robert Curry, and Mary E. ]Mr. ;^Ic^\'illiams has
always been an active worker in the Democratic party; in the winter
of 1883-84 he represented Northumberland county in the State
legislature, and was a member of the committees on military,
election, federal relations, and banking. He has also tilled various
township otlices. He is a member of Eureka Lodge, No. 404, F. &. A.
M., a charter member of Warrior Run Cha]iter, No. 240, and a
member of the S. P. K. uf Northumberland. He is a deacon and elder
in the Presbyterian church of Northiimberlaiid. Henry Watts, farmer,
was born at his present homestead, October 11, 1817. His father,
John Watts, was a native of England, who immigratetl to America in
1801 and settled ui^on the farm on which our subject now resides
in 1 M t2. He married in this country, Sarah Hales, also a native of
England. He was a Whig in politics, and his wife was a member of
the Bai^tist chitrch. He died in ISHO. and his widow in 1854. They
reared three children: Henry: John, and William, of Des Moines,
Iowa. The subject of this sketch was reared and educated in Point
township, and has always lived upon his present farm. In 1847 he
married Lydia Ann, daughter of Peter and Margaret (Giest) Dentler,
of Point township. They have no children. Mr. Watts is an active
Republican, and has served on the election board twenty-five years,
as asses.sor of the township eight years, and as school director a
number of terms. Mr. and Mrs. Watts are members of the Baptist
church of Northumberland.
lion HISTORY OF NORTHUMBERLAND COUNTY. H. W. Burg,
physicican and surgeon, was born in Lower Windsor, York county,
Pennsylvania, May 10. iSo'i. He received his literary education at
New Berlin, Union county, the W'illiamsport Seminary, and at a
commercial college. He read medicine with Dr. S. W. Burg, of New
Berlin, attended lectures at the Jefferson Medical College, from
which he graduated in 1877, and has since practiced his profession
in Northumberland. In 1875 he married Cora H., daughter of A. C.
Simpson, attorney at law, of Selinsgrove, Pennsylvania, by whom he
has three living children: Edwin; Stoddard, and Dorothy. A daughter,
Mary Blanch, was born, December 23, 1882, and died on the 13th of
October, 1SS-"). The Doctor is a Democrat in politics, has served as
burgess and assessor of Northumberland, and is a member of the
Sunbxtry Medical As.sociation. His wife is a member of the Episcopal
church. His father, Philip William Bur^. was a native of Amsterdam,
Holland, came to America when a young man. and settled in York
county. He married Mary A. Eckert, a native of Nurthmuberland, and
lived in Y'ork county iintil 1855, when he died, and his wife and two
sons removed to Northumberland in the same year. They had two
children: H. W., and Somers, a machinist of Danville. CHAPTP]R
XLVIII. BIOGEAPHICAL SKETCHES. TLU15LT AND ( HrLMS(JL'AQUK
TOWNSHIPS. Michael Follmeb, born in Germany in 1723, was the
father of six sons and three daughters, and died in 17'J3, aged
seventy years and three days. He and his sons donated the site of
the Follmer Lutheran church, and a farm of eighty acres to the
congregation, and, with his wife, ho was buried in this church yard.
He left a tract of land near Milton to his sixth son, Henry Follmer, an
active member of the church, who married Susan Stohl, by whom he
had iive children: Philip: Andrew; Thomas; Maria, and Elizabeth. He
died in 1822, aged tifty-four years and nineteen days, and his widow
died in 1861, aged eighty-nine years, eleven months, and nineteen
days. Andrew Follmer, the second son of Henri- Follmer, inherited
sixty-eight acres of land, upon which he reared two sons. Henry P.
and Reuben T. ; the latter is dead. He obtained a common school
education, and was an elder of the Reformed church at the time of
Welcome to our website – the ideal destination for book lovers and
knowledge seekers. With a mission to inspire endlessly, we offer a
vast collection of books, ranging from classic literary works to
specialized publications, self-development books, and children's
literature. Each book is a new journey of discovery, expanding
knowledge and enriching the soul of the reade
Our website is not just a platform for buying books, but a bridge
connecting readers to the timeless values of culture and wisdom. With
an elegant, user-friendly interface and an intelligent search system,
we are committed to providing a quick and convenient shopping
experience. Additionally, our special promotions and home delivery
services ensure that you save time and fully enjoy the joy of reading.
textbookfull.com