This video introduces the curl operator from vector calculus, which takes a vector field (like the fluid flow of air in a room) and returns a vector field quantifying how much, and about what direction, the flow is locally rotating, or swirling, at every point. The curl is a fundamental building block in vector calculus, and is used to measure the vorticity in a fluid. A tornado is a region of high curl. @eigensteve on Twitter eigensteve.com databookuw.com This video was produced at the University of Washington %%% CHAPTERS %%% 0:00 Introduction & Overview 5:22 Simple Example 9:07 Interpretation of the Curl 15:02 Intuition for Curl as Solid Body Rotation 24:29 Curl(Grad)=0 and Div(Curl)=0