1. Make a cone out of paper and tape. Cut its base straight, so that the cone stands perpendicular upward. 2. Measure the height and the radius of the base. 3. Photograph the cone. 4. Express the height of your cone in cylindrical coordinates (r,phi,z). 5. Find the gradient. In which direction does the gradient point? 6. Find the divergence of your cone. Should the divergence be negative or positive? 7. Find the curl of the gradient field of your cone.