Khan Academy Static

Flux can be view as the rate at which "stuff" passes through a surface. Imagine a net placed in a river and imagine the water that is flowing directly across the net in a unit of time--this is flux (and it would depend on the orientation of the net, the shape of the net, and the speed and direction of the current). It is an important idea throughout physics and is key for understanding Stokes' theorem and the divergence theorem.

6775_Vector_representation_of_a_surface_integral.html

6773_Conceptual_understanding_of_flux.html

6774_Constructing_a_unit_normal_vector.html