Start with a clear glass or plastic jar, some stripped wire, a strip of aluminum foil, and a larger piece of aluminum foil.
Bend the wire over the top of the jar so that it goes over the middle and is wrapped around the opening of the jar. Now fold the aluminum foil strip over and drop it over the wire, so that it hangs down into the jar.
Next take the larger piece of aluminum foil: make it roughly circular by cutting or folding the corners underneath, and press it over the top of the jar. Next wrap electrical tape (or any tape) over the edges of the aluminum foil holding it to the jar. Finally smooth out any bumps in the foil.
Your electroscope should look something like this.
Comb your hair a few times and hold the comb close to the top of the electroscope. The ends of the aluminum foil should push away from each other because of electric charge.
You can discharge the scope with your hand while holding the comb close to the top of the scope.
Move your hand away.
Move the comb away.
A charge has been induced into the electroscope. When you were discharging the scope charge remained close to the comb and when you moved the comb away that charge was released to spread through the rest of the metal parts including the aluminum strip.
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