Untitled Document

Physics Demo Number: 139

Approximate

Run Time: 10 min

Leybold Parallel Plate Capacitor With Dielectric Removable Insert

Demo Description

Use a capacitor and an electroscope to see the effect of dielectric insertion between the plates of a capacitor.

Scientific Principles

Two metal parallel plates in close proximity can affect the way charges distribute themselves.
Inserting a dielectric in a parallel plate capacitor changes its capacitance.

Equipment

Parallel Plate Capacitor
Dielectric Insert
Charging Rod and Fur
Overhead Electroscope

Equipment Location

Kit (139) on [B-1-1]
Kit (139) on [B-1-1]
Kit (139) on [B-1-1]
Kit (139) on [B-1-1]

Instructions

The first photo shows the capacitor with a relative charge of 1.5 as displayed by the overhead projector and electroscope, with the hanging piece of dielectric not inside the plates.

The second photo shows a view at right angles to the first, with the overhead projector turned off.

The third photo gives a view of the charge reading with the dielectric in place between the plates.

Here the reading has gone down to about 1.3. The fourth photo shows the view of the second arrangement from the side with the projector turned off.

All equipment but the hardware pole is in Kit (139).