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Electrostatics Basics
Name: Sally
Status: other
Grade: K-3
Location: N/A
Country: N/A
Date: 5/31/2005
Question:
I'm helping my son, in grade 2, with an experiment. We
took Rice Krispies and put them on a table, placed wooden blocks on
either side of the Rice Krispies and a Plexiglass on top of the blocks
(and rice Krispies). Next, we took a wool sweater and rubbed the
Plexiglass and the Rice Krispies started jumping and touching the
Plexiglass. How do I explain what is happening to my 7 year old?
Replies:
Sally,
I can think of no easy way to explain static electricity to a 7 year old
child without some sort of reference. I do not expect electric charge is
yet workable. The closest model a child of that age will have to work with
is magnets.
Magnets usually affect metal. This is something any child that has played
with magnets will know. If your son has not yet played with magnets, I
recommend such an experiment as the next step. If your son does know of
magnets, you have somewhere to start.
Static electricity is related to magnetism. Unlike charges attract and like
charges repel, just like magnetic poles. However, static electricity works
for many materials that are not magnetic. When you rub the plastic with the
wool, some of the negative charge (i.e. electrons) moves from the wool to
the plastic. Just like a magnet can pick up metal, the charged plastic can
pick up Rice Krispies. Another example is rubbing a balloon on your hair
and sticking it to the wall. This is very much like sticking a magnet to a
refrigerator. The difference is that it used static electricity rather than
magnetism.
I am sure you can refine the explanation to fit your son, but I hope it is a
good place to start.
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
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