Making an Electroscope

More about static electricity here

Instructions by middle school aged guest scientist Akash Srivastava from India

Akash did not have access to a digital camera, only a scanner. However, the author's fine illustrations are clear.

I built the project because I like to know that what kind of charges do different materials when rubbed with our hair(that is another use of an electroscope). This I do by charging the electroscope negetively(comb rubbed with hair) and then touching the object whose charge is to be checked. If the leaves diverge more, the body has a negetive charge and if the leaves collapse, the body is positively charged.

Here are the instructions-

Materials needed-

Foil paper--The kind that you buy in a roll will work, but the thin kind used to wrap chocolate to preserve its freshness works better.


A transparent jar



Cello tape


Cut a peice of cardboard into a circle little bigger than the jar. Make two 1cm long slits 1cm away from each other. Fig(1)

Take a 11cmX2cm foil paper piece. Insert it into the slits. Fig(2)

Take a large peice of foil paper and cover the cardboard circle with it.

Tape the cardboard circle on the mouth of the jar so that the leaves go into it.

The electroscope should look like Fig(3)

To see wether it really works or not, just rub a plastic comb with your hair and bring the comb in contact with the cardboard (covered with foil paper). the foil leaves which are inside the jar should move apart. Editor's note: Static electricty experiments work best on low-humidity days when the air is very dry.

The leaves move apart because when we touch a charged body to the disc of our electroscope, the leaves get the some charges as that of the body, like charges repell each other, so the leaves move apart.