The SESAME Colloquium

Dots: A Global Mathematics Phenomenon

James Tanton

Berkeley School of Education, University of California, Berkeley

Abstract

On October 10, 2017, the world witnessed the launch of the inaugural Global Math Week, during which more than one million students and teachers from 168 countries and territories engaged together in a single, joyful piece of classroom mathematics. Since then, the program has grown organically to reach more than 7.8 million learners worldwide (as far as we can count!).

At the heart of this global movement lies a single mathematical story—one that connects grade school, high school, and college level mathematics (and beyond!) through a simple yet astonishing visual construct.

In this session, we will explore the remarkable power of dots and see how this one visual idea can lead to deep and surprising mathematical insights. Participants will experience firsthand what joyful, creative mathematics can feel like in practice. Please bring pencil and paper—and perhaps an extra pair of socks, as this session may well knock your first pair right off!

About the speaker

James Tanton (PhD, Princeton 1994, mathematics) writes books, makes videos, advises on curriculum, consults with teachers, and gives demonstration classes and professional development sessions across the globe. He has taught mathematics both at the university and high-school levels and is absolutely committed to promoting effective and joyful mathematics thinking, learning, and doing at all levels of the education spectrum.

James has recently arrived to the San Francisco Bay Area and currently serves as an Associate Coordinator of Public Programs for BSE. He is also the Mathematician‑at‑Large for the Mathematical Association of America, co-founder of the Global Math Project, and Chief Mathematics Officer for SmartWithIt.

Title "What's on Your Mind?"

This meeting is an opportunity for students to have an informal conversation about what they're thinking about these days.

Mind the Gaps: Robust Strategies to Handle Missingness in Datasets

Kamal Chawla

College of Education and Human Development, University of Maine

Abstract

Missing data are a common challenge in education research—whether in classroom-based studies, large-scale assessments, or administrative datasets. Yet researchers often rely on ad hoc strategies such as listwise deletion or mean substitution that can introduce bias and underestimate uncertainty, ultimately leading to misleading conclusions about students, teachers, and schools. This talk offers a practical, evidence-based roadmap for addressing missing data in ways that strengthen the validity and interpretability of educational research findings.

I begin by unpacking the mechanisms behind missingness (MCAR, MAR, MNAR) using intuitive, education-relevant examples (e.g., student absences, skipped survey items) to clarify when “ignorable” approaches are appropriate. I then compare modern estimation methods—such as full-information maximum likelihood and multiple imputation using machine learning—highlighting when each is most effective, how to avoid common pitfalls (e.g., over- or under-imputation), and how to handle complexities like classroom clustering, nonlinear relationships, and interaction effects. Participants will leave with a clear understanding of how to identify missing data mechanisms in their own research and select appropriate strategies to address them.

The session concludes with guidance on conducting transparent sensitivity analyses (e.g., delta adjustments, pattern-mixture models) to evaluate how conclusions might change under different assumptions—an essential step for making robust and responsible inferences in education research.

About the speaker

Dr. Kamal Chawla is a statistician, meta-analyst, and missing data specialist who serves as an Assistant Professor of Education & Applied Quantitative Methods. His work is at the intersection of machine learning, missing data, and meta-analysis, and he is dedicated to leveraging advanced quantitative methods to address critical challenges in education.

Dr. Chawla’s research agenda is twofold: methodologically, he focuses on developing and refining research methods through data science and machine learning techniques to produce robust and unbiased outcomes. On the applied side, his research focuses on enhancing student learning in elementary and secondary classrooms by developing teaching strategies that are not only effective but also tailored to the diverse needs of individual students. By integrating these cutting-edge techniques, Dr. Chawla’s work aims to bridge educational gaps, empower students from all backgrounds, and contribute to a more prosperous society.

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Michelle Wilkerson

Berkeley School of Education, University of California, Berkeley

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Discovering the world of viruses: How children think and learn about germs and illness

David Menendez

Psychology, University of California, Santa Cruz

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The COVID-19 pandemic showed the importance of having a robust understanding of illness transmission. However, topics related to illness and germs are rarely covered in elementary school science curricula, despite aligning with the cross-cutting themes of the Next Generation Science Standards. I will present recent empirical work examining how 5- to 12-year-old children across the United States think about illness and viruses. This work shows how children understand the observable processes involved in illness transmission, but have difficulty reasoning about the unobservable aspects, including the nature of viruses.

Then, I present the results of an at-home educational intervention where children read a storybook detailing the observable and unobservable aspects of illness transmission. Critically, we manipulated whether detailing unobservable processes, and whether the representations in the book were realistic or anthropomorphized. This study shows that storybooks are an effective way to teach children about viruses and illness, provided they explain unobservable aspects. Children learned equally well from anthropomorphized and realistic books. This work highlights how children have learn complex scientific topics at an early age.

About the speaker

David is an assistant professor of Psychology at the University of California-Santa Cruz. His research examines how people learn concepts in formal and informal settings. He has explored how children learn science concepts through conversations with parents, when and why people change the strategies they use to solve mathematics problems, and how visual representations influence learning and generalization.

He is also interested in the role of culture and socialization practices on development, including how participating in cultural rituals shapes children’s conceptual development, and how different communities within the United States think about illness.

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Circle-ometry (aka Trigonometry): The Story and the Mathematics

James Tanton

Berkeley School of Education, University of California, Berkeley

Abstract

Why is the trigonometric ratio “opposite over hypotenuse” called sine, a word derived from the Latin sinus, meaning a “twisty” or “curved” feature? What curious historical quirk led to this name? And why is the tangent ratio named using a term drawn from geometry?

In this session, we will explore the delightful story of trigonometry from its historical beginnings—beginnings that one might argue are also the most natural starting point for young learners.

The modern emphasis on right triangles (and even the term trigonometry itself) emerged relatively late in the subject’s development and often provides little initial context for students.
Come see what familiar curriculum topics look like when they are re‑introduced in their natural historical order, allowing delight, intuition, joy, and depth of understanding to come to the fore.

About the speaker

James Tanton (PhD, Princeton 1994, mathematics) writes books, makes videos, advises on curriculum, consults with teachers, and gives demonstration classes and professional development sessions across the globe. He has taught mathematics both at the university and high-school levels and is absolutely committed to promoting effective and joyful mathematics thinking, learning, and doing at all levels of the education spectrum.

James has recently arrived to the San Francisco Bay Area and currently serves as an Associate Coordinator of Public Programs for BSE. He is also the Mathematician‑at‑Large for the Mathematical Association of America, co-founder of the Global Math Project, and Chief Mathematics Officer for SmartWithIt.

From intuition to intention: co-constructing design principles for embodied science instruction with teachers

Magdalena Kersting

University of Copenhagen, Department of Science Education

Abstract

Here's a puzzle: science teachers regularly use movement, gesture, and physical experience in their instruction. But ask them why it works, or when to deploy these approaches strategically, and you will often get a shrug. Meanwhile, embodied cognition research offers compelling theoretical frameworks and insights that rarely make it into classrooms. What happens when we bring these two worlds together?

In this talk, I present findings from SENSES (Science Education Network for Supporting Embodied Sense-Making), a participatory network in which science education researchers and secondary science teachers in Denmark spent 12 months collaboratively developing design principles for embodied instruction. Through iterative cycles of co-design workshops, classroom implementation, and collective reflection, we transformed tacit pedagogical intuitions into explicit, actionable principles – while deepening our collective understanding of embodied learning processes along the way.

I'll share the design principles that emerged and explore what the process reveals about building productive research-practice partnerships. But I'm equally interested in the meta-question: What can embodied cognition research learn from science education practice? I'll argue that collaborative inquiry, honoring both theoretical and practical expertise, generates insights neither could develop alone – and that the messy realities of classroom practice do not just apply theory, they can refine and extend it.

About the speaker

Magdalena Kersting is an assistant professor of science education at the University of Copenhagen, where she explores how embodied experiences shape scientific understanding. Drawing on an interdisciplinary background in mathematics, physics, and science communication, she leads the SENSES network, bringing together researchers and teachers to develop embodied approaches to science instruction, and co-founded IMPRESS, an international seminar series on modern physics education in collaboration with CERN.

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Mengyan Fang

School of Education, Shaanxi Normal University, China

Josh Medrano

Berkeley School of Education, University of California, Berkeley

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Learning in and out of school: A cultural-developmental perspective

Geoffrey Saxe

Berkeley School of Education, University of California, Berkeley

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This brownbag examines learning in collective practices—such as recurring classroom activities and the everyday play of toddlers and caregivers—where mathematical understanding emerges through moment-to-moment activity. Traditional approaches to learning in such settings often emphasize individual development (ontogenesis) while giving less attention to how conventional representations and ideas are reproduced and transformed in community talk and action (sociogenesis). I argue for an integrated cultural-developmental framework that centers microgenesis—the moment-to-moment construction of meaning in activity—as the key link between individual and sociocultural developmental processes. Microgenesis is defined here as the construction of numerical meanings as individuals use representational forms to serve evolving cognitive functions in collective practice.

Drawing on three research programs, I illustrate how tracing form–function relations across micro-, onto-, and sociogenetic processes illuminates learning in and out of school. The first examines mathematical learning among the Oksapmin of Papua New Guinea, who traditionally use a 27-body-part number system, documenting shifts in form–function relations in practices of exchange and schooling across four field visits spanning more than 30 years. The second focuses on early number development among 2½- and 4½-year-olds in Brooklyn, NY, analyzing family practices that support children’s expanding uses of number words for functions such as cardinality, comparison, and reproduction of quantities. The third investigates children’s developing understandings of integers and fractions, with particular attention to instructional practices that support new uses of representational forms such as number lines, drawing on interview, design-based, and experimental studies.

Together, these projects demonstrate the value of a cultural-developmental approach that coordinates analyses of moment-to-moment activity (microgenesis), individual development (ontogenesis), and the evolution of community representations and practices (sociogenesis) for advancing theory and informing educational design.

About the speaker

Geoffrey Saxe is Distinguished Professor of the Graduate School at UC Berkeley. His research explores the mutual shaping of cultural practices and cognitive development, spanning diverse settings—from NYC family interactions and US classrooms to communities in Papua New Guinea and Brazil. Supported by the National Science Foundation, the Spencer Foundation, and the Institute of Education Sciences, his work has been honored with fellowships at the Center for Advanced Study in the Behavioral Sciences and the Rockefeller Foundation’s Bellagio Center. 

Saxe has authored influential books, including Social Processes in Early Number Development (1987) and Culture and Cognitive Development (1991). His book, Cultural Development of Mathematical Ideas: Papua New Guinea Studies (2012), achieved the rare distinction of winning Outstanding Book Awards from the Cognitive Development Society, the American Anthropological Association, and the American Psychological Association. A member of the National Academy of Education and an inaugural Fellow of the American Educational Research Association (AERA), he served as President of the Jean Piaget Society and Editor of Human Development. He was recognized with two AERA Presidential Citations in both 2010 and 2022.

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Kelly Billings-Yadav

Berkeley School of Education, University of California, Berkeley

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Catalina Lomos

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Alik Palatnik

The Seymour Fox School of Education, The Hebrew University of Jerusalem, Israel

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