An electroscope is a device that detects static charges or electrostatic field. You can make a simple one. Go to your kitchen and get an aluminum foil. Cut two equal pieces of area 5 cm long and 1 cm wide. Hang the pieces (let's call them leaves) in a paper clip or any piece of metal. Approach the leaves to a TV screen and you will observe that the leaves repel each other. The reason is that the TV screen produces electrostatic field due to HV circuit. The field induces the same charges in the aluminum and consequently the leaves repel each other. Like charges repel and unlike chrages attract. Simple! This was demonstrated by Mustafa Daif assisted by Sharif Ahmed.
