The electroscope is an early scientific instrument used to detect the presence of electric charge on a body. It detects charge by the movement of a test object due to the Coulomb electrostatic force on it. The amount of charge on an object is proportional to its voltage.

There are three classical types of electroscopes: pith-ball electroscope (first), gold-leaf electroscope (second), and needle electroscope (third).

WORKING OF AN ELECTROSCOPE : In an uncharged electroscope, the leaves hang straight down. When a charged object touches the metal knob, electric charges travel down the rod and into the leaves. The leaves spread apart, indicating the presence of an electric charge.

An electroscope consists of a vertical metal rod that sticks out of a glass enclosure; a piece of plastic​ ​prevents electric charge from going from the metal rod and metal leaves at the bottom on to the cylindrical enclosure, which is usually metal as well.

Gold leaf electroscope has two gold leafs suspended from a metal(usually brass) stem in a vacuumed glass jar and connected to a metal cap. The glass is grounded with the help of a metal foil to make it uncharged. It can be used to: Detect charge: Body under test is touched with the metal cap.

How to make your own Electroscope:

1. a glass jar,
2. 2 little pieces of aluminium foil cut into small round shapes (and you need to put a whole in one end of each foil);
3. A copper wire (spiral one of the ends of the wire to make a large surface area);
4. Some electrical tape,

The electrons, which are negatively charged, can then travel through the copper wire of the electroscope down to the pieces of foil, which both become negatively charged. These negative charges push against each other, causing the pieces of foil to repel.

if your electroscope dont work then check: 1)whether you have accumulated any charge or just sent them to ground. 3)make sure the aluminium does not have paper type non conductive layers on it.

When the positively charged electroscope is touched, its charge becomes grounded (or neutralized). The negatively charged electrons enter the electroscope and neutralize the positive charge. As the electroscope loses its charge, the needle relaxes back to its naturally upright position.

When we touch the metal top of a charged electroscope with our finger, the charges pass through us and into the ground. This process is called as earthing.

When you remove your hand and the charged rod, the leaves spread apart, indicating a positive charge has been achieved due to the loss of electrons. The positive charge in the leaves is then neutralized, and the leaves collapse.

A glass rod becomes positively charged when rubbed with silk, while the silk becomes negatively charged.