Here is another useful activity to learn something from.
I just invented and verified it. Or perhaps I read about it
somewhere and do not remember. If so then I apologize
for the unjustified claim. In any case it is trivial.
Let two 4" tapes to be bound with their sticky sides
toward each other. Make sure the tapes are neutralized
before separating them. Then pull them apart and
discover that they do not attract. This can be contrasted
with strong attraction which exists between the tapes
which had one sticky side sitting on the smooth side
before the separation. Make sure each tape has a good
strong handle; it is a little harder to separate two sticky
surfaces.
What does this experiment demonstrate? It shows that
no significant separation of unlike charges occurs when
surfaces are nearly identical.
Ludwik Kowalski