Friday, July 6, 2012

Electroscope - Static Electricity

In one of my Science classes at high school, the teacher had shown a lab model of Electroscope. [Click on this link to know what it exactly is]  It was a gold leaf electroscope. He rubbed an ebonite rod on a piece of woolen cloth and held it on the electroscope.  Lo, it made the two leaves inside the sealed jar repel! That was the simple lab demonstration of the static electric charges.

[Web-grab image from 'Museum of Technology']

I was impressed by this mysterious phenomenon called static electricity from the plastic/synthetic comb at home where we did 'magic' to the wonderment of our grandmother!  We made little paper pieces move and stick to the comb!  It was thrilling to fool her. 

Small plastic covers were also used for this 'magic', for fun. See this link where [click] you can relive your younger days!  It is pleasing to know from that link that I had made similar ones in 1973 itself, particularly the electroscope! 

TV screens, among myriad items produce it. If you just google 'static electricity', you will be amazed at the long list of available information on this curious thing.

You can experience a shock about 8-10 Volts and that is about the amount of current that zaps across.  It was funny when my colleague demonstrated and startled me with two plastic chairs.  I saw the spark zap across from the 'charged' person to another as the fingertip closed in on the other person.  It can be quite a prank!

Some synthetic dresses, especially a fabric called Terylene which was a fashion in the late 60s and early 70s also produced static electricity. I used to wonder why shirts of this fabric gave a weird feeling to the hands as we brushed them against while walking.  Even while removing it, esp. in the dry winter months, it used to get attracted to our skin and make our hair on the hands stand on end! The plastic wire bags that my aunt had woven also gave this same experience. 

So when the lessons on Static Electricity were made in the class, we used to listen very curiously! 

Why not I make one, just for the heck of it?!  It serves no purpose at all, yet, it was another little project I thought. "Scientific temper!"  Around that time, my grandfather had been afflicted with 'neuritis' after he exposed himself to cold winds traveling in a bus to Bangalore and had lost sensation in his fingers.  So, 'Neurobion' was prescribed to him. The capsules came in little bottles with a rubber stopper.  An empty one suited my project. Since I could not think of gold leaf at all, I used aluminum foil from a tin can.  A brass pin from a broken electric plug came in handy to fix it to the stopper and hang the foils with a thin wire.  I used my comb to see if it repelled the foils.  It worked! The foils reacted slightly. That was enough satisfaction, even though it is the most useless thing! 

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