the triangle Austin, TX 2011/07/17 A couple of years ago, I wrote a little program about triangles. The program calculates the area of a triangle given the base and the height. No great feat, right? Except, I did a little something special with the user interface. The triangle is graphed in a good old Cartesian … Continue reading Triangles
Austin, TX 7/7/2011 For millennia, humans have loved to operate with mathematical objects. We started with shapes. We moved them around, flipped them over, and even “added” them, laying them side-to-side. Then, we went to town on numbers, and the town grew to a metropolis of operation neighborhoods: addition, subtraction, multiplication, division, and exponentiation. From … Continue reading Binomial Squared
47th & 7th, NYC 5/29/2011 A few days before I left for New York, my friend Jason said, “You should put the formula for time dilation in Times Square.” Brilliant! I am not sure if we made it to Times Square proper, but there was bright light, noise, and people at the corner of W … Continue reading Time(s Square) Dilation
W 4th St Station, NYC 5/29/2011 I had a lovely day with dear friends Marlowe, Yasmina, and their little ones, Elia and Aviva. Marlowe encouraged Laurie and me to go to Babbo for dinner. I had the mushroom sformato, squab, and panna cotta. It was delightfully delicious. The spirits of New York and Europe were alive … Continue reading Fibonacci Numbers
Madison Square Park, NYC5/28/2011 I was in NYC for a friend’s wedding. Big plans for the city: food, subway rides, Central Park, the Upper East Side, and chalk. On Saturday morning, I hopped a train to midtown and headed into Madison Square Park. The park had a large sculpture from Jaume Plensa. It stopped me … Continue reading Hexagons
Texarkana, AR & TX 7/8/2010 It has been more than a few months since I bore the heat of July to leave the distributive property across the state line. Laurie and I followed our noses down N State Line Avenue with Arkansas on our left and Texas on our right. For a moment I considered … Continue reading Distributive
St. Louis, MO 7/6/2010 Sometimes, people try to tell me the arch in St. Louis is a parabola. I am pretty sure it is not. A better model for the curve of the arch is the catenary – the path a hanging chain marks out. Granted, to get the Gateway to the West, you would … Continue reading Hyperbolic Cosine & The Arch
Grand Rapids, MI7/3/2010 Here’s what you should know about the corner of Bostwick and Crescent in downtown GR: I had my first algebra class in a building on that corner. On the third floor, I had Algebra 1 with Mrs. Molloy. I am sure that was the first time I spent any quality time with … Continue reading Graphing the Quadratic Formula
Champaign, IL6/28/2010 The seedling of this whole chalky project was born when I walked past a parking ramp at Colorado and 9th in Austin, Texas. The multiple-storied wall of this ramp is covered in 4 or 5-foot square squares of cement. It looks like enormous graph paper. I have this dream of putting some sine … Continue reading Sine & Cosine
Effingham, IL 6/27/2010 My first math donation in chalk occurred outside of the Helen Matthes Library. Something about Effingham was compelling, and how could I pass up the “Matthes”? So, the project began with a little riff on slope-intercept form. Many people recall slope-intercept form. Maybe not the name, but folks tend to feel a … Continue reading Slope-Intercept Form
Footpath Math: Chalk it up to a math geek 