Like other enthusiasts of mathematics, I’m captivated by the way that mathematical ideas can explain things in the physical world around me, and by the way that I can carry out mathematical thought experiments in my mind and then apply the results to control my external physical environment.
In the Dynamic Number project, one of our goals has been to create activities in which students actually experience mathematical objects by creating them, manipulating them, and investigating them. (George Lakoff and Rafael Núñez describe, in Where Mathematics Comes From, how students' abstract mathematical concepts are grounded in … Continue Reading ››
As an 18-year veteran teacher in Philadelphia public schools, my initial reaction when I first saw Sketchpad was “This would have completely changed the way I taught geometry.” I phrase it differently today: “This would have completely changed the way students experience mathematics.” a perspective that differs in two important details. First, I now understand that the … Continue Reading ››
After writing yesterday's post on the connections between polar and Cartesian graphs, I realized that I hadn't said anything about how easy it is to start from scratch and create a polar graph in Sketchpad, so I decided to write this post, and include an instructional video. Here are … Continue Reading ››
The May 2013 Mathematics Teacher has an excellent article by Jonathan F. Lawes ("Graphing Polar Curves") on the value of plotting the same function in both polar and rectangular coordinates. Doing so not only helps students understand how polar coordinates work, but also gives them a novel and revealing … Continue Reading ››
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 ››
Not long ago, I conducted a Saturday morning PD session for some Texas teachers participating in an NSF research project. (The research is a controlled study of the relationship between students’ use of Sketchpad and their conjecturing and proving behavior. I hope we’ll have a blog post about this study itself before too long.) Because of the … Continue Reading ››
Functions are hard for students. Students seem to master various families of functions – linear, polynomial, exponential, trigonometric, and so forth. They can graph them, evaluate them, transform them, and answer a variety of questions about them. But ask even our better students a question that’s out of the ordinary and we’re likely to be taken … Continue Reading ››