Make Paper and Cork Dance under Glass
You will need: A small pane of glass, two books,
silk handkerchief, tissue paper, cork, glycerin.
It is surprising to see how
easily and quickly a charge of static electricity can be induced in a pane of
glass by rubbing it briskly with a silk handkerchief.
the ends of the glass between the pages of two books, raising the glass so that
it is about J inch from the top of the table. Tear some tissue paper into tiny
scraps and spread these out below the glass. Rub vigorously on top of the pane
with the piece of silk. Within a few seconds the scraps of tissue paper will
appear to 'dance' in a lively manner as they are attracted by the static charge
of electricity that you are producing in the pane of glass.
A variation of this
experiment is to replace the tissue paper with tiny pieces of cork (obtained by
cutting and chopping an ordinary bottle cork). These can also be made to 'perform'
once you have induced a static charge in the pane of glass.
It is possible to produce a sufficiently strong charge of static electricity so that the scraps of cork will hang from the underside of the glass like miniature stalactites.
If you really wish to surprise your friends, however, tell them that the pieces of cork are so obedient that you can make them form the initial of your name.
The secret of this trick is to first have your pane of glass suitably prepared. This is done by smearing an outline of glycerin in the shape of your initial on the underside of the glass.
When you now rub the top of the glass with the silk handkerchief, the pieces of cork will be attracted to the underside. Where they come into contact with the glycerin they actually adhere to the glass.
Stop rubbing the glass and the pieces of cork outside the glycerin outline will fall back to the table, leaving your initial clearly 'written' in cork chips.