Note: To read this active essay, you need to download the MicroWorlds Logo plugin. Going in Circles 

What is a circle? When you see a circle, how do you know it's a circle? When you want to make a circle, how do you do it? Click Go. Each of the turtles walks forward. Together, they make an everexpanding circle. This example highlights one way of thinking about circles: A circle is all of the points at a fixed distance from a given point. Since all of the turtles start at the same place, and all walk at the same speed, they stay equidistant from the starting point. So they always make a circle. 

This is just one of many ways of thinking about circles. In this essay, we'll be exploring many other ways of making circles. Each approach will highlight a different aspect of "circleness." In the process, we will explore not only how to make circles, but also how to think about circles  and perhaps how to think about things in general. 

Go to the next page or the contents page. Mitchel Resnick and Brian Silverman Epistemology and Learning Group MIT Media Laboratory Last modified: November 17, 2003 