Static Electroscope
A jar and a strip of foil reveal invisible static charge by spreading apart on their own.
Start building ↓The build
Make the lid
Push the wire through a card lid sealing the jar.
Hang the leaves
Bend two thin foil strips over the wire's bottom hook.
Add a top plate
Curl foil onto the wire top outside the jar.
Charge it
Rub a balloon and bring it near; the leaves fly apart.
A charged object pushes like charges down to the foil leaves; since both leaves get the same charge, they repel and spread apart.
A closer look
It detects the presence and relative size of static charge through electrostatic repulsion between like charges.
Variables to test
- 1 Touch the plate to discharge — do the leaves fall?
- 2 Compare wool, plastic and hair for charge strength.
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