Dielectric Constants and the Parallel Plate Capacitor: Doing It Right!

Document Type

Poster Session

Presentation Date

Summer 7-19-2010

Conference Name

2010 Summer Meeting of the American Association of Physics Teachers

Conference Location

Portland, OR


One common and seemingly simple laboratory investigation of capacitance consists of inserting multiple sheets of paper (or other thin dielectric materials) between two conductive plates and measuring the capacitance of the system. The separation of the two plates is nominally determined by the number and thickness of the individual dielectric sheets. The end result of this investigation is to determine the dielectric constant of the sheet dielectric. Unfortunately, this is seriously flawed because of air trapped between the dielectric sheets. The calculated dielectric constant is too low because it is of a composite material or air and the dielectric sheet. We present a simple method of performing these measurements that does not have these shortcomings and provides more accurate values for the dielectric constant. Better yet, the described investigation is even simpler for students to perform.


physics, dielectric constant, lab, education


Curriculum and Instruction | Physics

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