Electricity and Magnetism > Capacitance > Capacitors DCS# 5C10.20 v.3
CAPACITOR AND DIELECTRIC
APPARATUS
large aluminum capacitor plates with spacers
 202-19-A
plexiglass or bakelite sheet
 202-19-A
capacitance meter
 202-10-B
camera
 202-09-C
grounded metal plate
 202-18-A

DESCRIPTION
The two plates form a parallel plate capacitor.  The plates are 50.7 cm square, so A = 0.257 m2, and the plate separation is 1 cm.  The plate separation is fixed by four plexiglas spacers.

The capacitance, determined using C =  εA/d, is 230 pF.  The measured value is 275 pF.
Use the grounded metal plate to remove any excess charge from the dielectric.  Insert the dielectric between the capacitor plates to show that the capacitance increases.  Remove the dielectric and the capacitance returns to its original value.

Demonstrate the dependence of capacitance on plate separation by gently pushing on the top flexible plate with a plexiglas rod.
The Pasco variable parallel plate capacitor can also be used for this.