This student activity is designed to help upper division undergraduate students work with non-constant charge distributions in electrostatics. Students are given various functional charge densities in spherical and cylindrical geometries and must determine the total charge. This activity requires them to work with various volume elements and integrating by substitution. An instructor's guide is available to help guide the activity along with the student handout.

This material is part of the Paradigms in Physics project at Oregon State University. This work promotes the use of active student learning in upper division physics courses. Both learning materials and learning strategies are provided to help both students and instructors.