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one pie tin to the dome of the Van de Graaff generator and stack the
rest of the pie tins inside the taped one. When you turn the
Van de Graaff generator on the dome and the pie tins all have the
same sign charge and thus repel. The same thing happens to the
Styrofoam peanuts when placed on top of the dome.
Some other things to put on a VDG so that they fly off: tin pie
plates, Rice Krispies in a cup, popcorn in a cup, cheerios. Hide popped popcorn in a
Styrofoam cup, pour in un-popped popcorn, turn on VDG and watch the
popped popcorn fly out.
Have the students hold Styrofoam peanuts in
their closed hand and touch the VDG. Turn the VDG on and when
they are charged have them open their hand and see the peanuts float
away.
Styrofoam peanuts in a metal vs. Styrofoam cup. In the
Styrofoam cup the peanuts will fly out, in the metal cup they will
not due to a Faraday Cage effect. Our "metal cup" for this
demo is a large copper mesh cup so that you can observe the action
of the peanuts when the VDG is turned on.
A Halloween version of this is to place the felt "bat" on the top
of the VDG. When the VDG is turned on, the bats head and wings
will lift up, and he will appear to be looking at you before he
flies away.
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