# Soccer Challenges: Angling for a Shot on Goal

With the World Cup in our hemisphere, and the US squad having started out with a win over Ghana, my thoughts turned to the mathematics of soccer. My friend Henri Picciotto has a nice page about the shooting angle, the angle within which a shot is on goal, so I thought of using … Continue Reading ››

# Drawing Ellipses with a Congruent Triangle Construction

Welcome back to my ongoing series in which I feature interactive Web Sketchpad models that draw conic sections. Today’s installment, like the previous one, focuses on ellipses, and dates back to the 17th-century Dutch mathematician, Frans van Schooten. Below is an image from Continue Reading ››

# Arthur Ganson and the Excitement of Construction

I first encountered the kinetic sculptures of Arthur Ganson nearly 20 years ago at the MIT Museum. Ganson is an engineer, artist, and inventor whose machines, when set in motion, display a grace you would not expect from metal, gears, and other industrial objects. Below is a video of one of … Continue Reading ››

# Wait for a Date

Consider the following probability question: Two friends arrange for a lunch date between 12:00 and 1:00. A week later, however, neither of them remembers the exact meeting time. As a result, each person arrives at a random time between 12:00 and 1:00 and waits exactly 10 minutes for the other person. When the 10 minutes have passed, … Continue Reading ››

# The Dog Leash Investigation

Today's guest post is from Marta Venturini, a PhD student in Mathematics Education at Simon Fraser University under a "Cotutelle Agreement" with the University of Bologna, where she's a PhD student in Mathematics. While looking for some tasks that would be suitable for Sketchpad,  I found the “dog leash” problem in a March 2007 Continue Reading ››

# The Wavy Wavy Bridge

At the 2013 Baltimore Regional NCTM Meeting, I gave a presentation on Picturing Functions and Functions of Pictures. In the description of my presentation I’d promised to show how to use Sketchpad to create special effects, so when it came time to prepare, I figured I needed to deliver on my promise. So I wrote a … Continue Reading ››

# What Does Rowing Have to Do with Teaching Mathematics?

Harry Parker died this summer, two weeks after coaching the Harvard rowing team to yet another sweep of all four races (varsity, JV, freshmen, and spares) against Yale and two days after accompanying his 1980 Olympic … Continue Reading ››

# Exponential Harmony with Sketchpad

Last week was the fourth session of my spring Advanced Secondary Math Methods class at the University of Pennsylvania. Each year I assign a semester project in which groups of three students use lesson-study techniques—on a small scale—to create, test, refine, teach, evaluate, and document specific shared instructional products, composed of a (possibly multi-day) lesson … Continue Reading ››

# Data Visualization in the Age of HTML5

My partner and I spend a fair amount of time talking about data visualization. He's a computer programmer who works on websites that gather and display large amounts of data related to energy production and consumption. This data can be used to answer questions like: "How effective is the California Solar Initiative?" and "Where in … Continue Reading ››

# Preparing Tomorrow’s Data Scientists Through Data Games

According to a recent Wall Street Journal article, "Big Data’s Problem: Little Talent," the technology industry faces a major dearth of employees with strong data analysis skills. The article quotes a 2011 study by McKinsey:
A significant constraint on realizing value from Big Data will be a shortage of talent, particularly of people with deep expertise … Continue Reading ››