This applet is designed to build intuition about divergence and curl of a vector field.

• The applet has a control window and Vector Field window. 
• The Vector Field window shows the the vector field V, and a red hot spot P0 that can be dragged.  The divergence at P0 is shown by a horizontal green bar.  The curl at P0 is shown by a vertical blue bar.
• The control panel lets you define the vector field V=(p,q).  It gives readouts for the value of P0 along with V, and its divergence and curl, all evaluated at P0.
• The control panel lets you set the viewing window along with the density and scaling factor of the vector field.