Elliott County Static 18
One of our 6th graders
favorite classes is when they take a look at static electricity and
what it can do and what it feels like.
Most of them know that a balloon can be charged by rubbing it on fur or hair.
It will then stick to anything carrying the opposite charge, say fur or hair for example.
They could also feel it attract the hairs on their arm when it was brought near.
Next we use a balloon, aluminum pie plate and a straw to light a fluorescent light bulb.
Tape the straw to the plate so that it can be held, insulated from ground.
Charge the balloon as before.
Bring the balloon close to the pie plate and touch the plate with your
finger to let the charges repelled by the balloon go to ground and the
ones attracted by it move to the plate through your finger.
Take your finger off the plate to isolate it from ground and move the balloon away.
The plate now has a charge that will cause the fluorescent light to
blink when you hold one end and touch the other to the plate.
You can also build an
electroscope with nothing more than a clean dry drink bottle, a paper
clip, a strip of metalized Mylar wrapping paper, and a bit of glue.
Here some students are testing the electroscope they made.
As the charged balloon is brought close to the paper clip it repells charges down to the Mylar film.
Now the two pieces of the film are charged alike, are repelled, and move away from the other.
We now can turn students into electroscopes.
The student stands on a plywood platform supported with glass jars to insulate them from the earth.
We use a Van de Graaff to supply high voltage.
When I say high think very high.
It can be a quarter to half a million volts.
There was no sensation other than a strange feeling as the hair on their arms and head moved.
Because each of the hairs are charged the same they repel each other with the following result.
His friends obviously liked the effect.
Him not so much.
More human electroscopes.
Then they wanted to see what a charge did to me.
Even after they leave go of the Van
de Graaff they remain charged and can give a classmate a little shock
if they touch a finger to their hand.
After being an electroscope they became conductors and lamps.
The first student held a pan against the Van de Graaff as the first link of a chain.
They held on to one end of a florescent bulb and another student held on to the other.
Then they continued the chain alternating kids and bulbs.
When I turned the Van de Graaff on the voltage built up and a small current began to flow.
The bulbs all glowed showing that the current was passing from one kid to the next.
Of course the current was passing through the kids too so they could feel it.
If the pan was held in contact with the Van de Graaff or very close to it the sensation wasn't too bad.
But if the student holding the pan moved it a couple of inches away everyone would would be shocked.
These pictures show both situations.
The students could take on the Van de Graaff one on one if they chose.
With it charged they could draw a spark to their hand ... truly shocking.
A piece of monofilament fish line
strung with alternating insulating and conductive beads also gave the
kids a chance to test their nerves.
One end of the beads is attached to the Van de Graaff and a student holds on to the other.
Initially there isn't enough voltage to jump from one conductive bead to the next but ...
As they slide their hand closer to the charged Van de Graaff there is a very sudden breakdown between the conductive beads.
The anticipation can be worse than the shock.
Great fun for all.
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