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An electroscope is a common demonstration apparatus used by physics teachers to illustrate electrostatic principles of charging and charge interactions. The electroscope is most commonly used as a charge-detecting device. The electroscope shown in the animation below consists of a plate (near the top), a support stand (which connects to the plate and extends through the center of the scope), and a needle which rests upon the support stand and is free to rotate about its pivot. The plate, support stand, and needle are all made of a conducting material which allows for both the free flow of electrons and the distribution of any excess charge throughout the electroscope. By observing any deflection of the needle, the presence of charge in either the electroscope or a nearby object can be determined.

One common demonstration performed with the electroscope involves the induction process of charging. In the induction process of charging, a charged object is brought near to but not touching the electroscope. The presence of the charged object above the plate of the electroscope, induces electrons within the electroscope to move accordingly. With the charged object still held above the plate, the electroscope is touched. At this point electrons will flow between the electroscope and the ground, giving the electroscope an overall charge. When the charged object is pulled away, the needle of the electroscope deflects, thus indicating an overall charge on the electroscope.