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Krampf #464 Oil and Water and Static, Oh My!
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KRA-@aol.com
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Jul 11, 2006 08:23 PDT
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Robert Krampf's Experiment of the Week
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This Week's Experiment - #464 Oil and Water and Static, Oh My!
Greetings from Ft. Lauderdale. I am still busily working on my science
video series, and am having a blast. I am also learning tons about the world of
video production, which really makes me appreciate all the work that goes into
the television that we watch every day.
This week's experiment is one that I came across while researching for the
science videos. I came across an article that compared the effect of static
fields on polar and nonpolar materials. Sound complicated? Really, it is
simple and amazing. To try this, you will need:
a balloon
water
oil
syrup
We will start with something that we have done before. Blow up a balloon
and tie it off. Then rub it against your hair or a piece of cloth, to build up
a static charge. If you bring the balloon near the back of your hand, you
should feel the hair standing up on your hand.
Then turn on the water in your sink. Turn the water down to form a very
thin stream of water. Bring the balloon near the stream of water, and you
should see that it bends towards the balloon. You may even see drops leap from
the stream to the balloon.
Now come the new part. We want to try the same thing with a thin stream of
oil. I put a bowl in the sink and then poured cooking oil into it, trying to
get a nice, thin stream like I had with the water. This time, when I
brought the balloon near the stream, it did not bend or react to the static charge.
Why?
Well, the article that I read said that it was because water is polar and oil
is nonpolar. What in the world does that mean? No, it doesn't mean that
you don't find oil at the North Pole. If a molecule is polar, then one part
of the molecule will have a positive charge and another part will have a
negative charge. Nonpolar molecules have a neutral charge all over. That should
mean that the polar molecules will be pushed or pulled by the electrostatic
charge on our balloon.
OK, so it seemed to work, but I was wondering if part of this was because the
oil was thicker than the water. To test that, I did the experiment again,
using some sorghum molasses (a thick syrup popular in the Southern United
States). Since it is water based, it is also a polar liquid. Instead of pouring
it into the sink, I poured a thin stream onto some nicely buttered toast.
The charge of the balloon did the same thing to the syrup that it did for the
water, showing me that even thick liquids are bent by the static charge. It
also made a nice, tasty design on my toast.
That lead me to wondering if the same thing applied to solids. Wax is a
nonpolar solid, while wood is polar. If solids react in the same way as
liquids, then you should be able to sort a pile of tiny bits of wax and wood by
bringing the balloon near the pile. Does it work? <grin> Guess you'll have to
try it to see. Why should I have all the fun?
Have a wonder filled week.
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From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
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