Circle of Curvature
The circle of curvature is a visual expression of the curvature of a curve at a given point. The circle of curvature, or osculating circle, of a curve at a point is the circle tangent to the curve with the same curvature. This Demonstration shows the circles of curvature along several curves.[more]
For a nice animation, run the two sliders simultaneously in the back and forth mode.[less]
H. W. Franke, Animation mit Mathematica, Berlin: Springer, 2002.
"Circle of Curvature"
Wolfram Demonstrations Project
Published: March 7 2011