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PIRA Class: 5A22.30
Purpose:
To demonstrate a means of relative measure of net charge.
Description:
Demonstrate charging by direct contact or charging by induction. The rotating arm will deflect more and more as the arm and central bar gain more and more charge, whether positively or negatively charged.
- Charging by induction: Place the object near to the electroscope, the electroscope top knob will acquire the opposite charge of the object at hand. The central bar and rotating arm will then have the same charge as the object. (Object's net charge is not changed during this process.) The closer the object is brought to the top knob, the greater the separation of charge within electroscope, the greater the deflection of the rotating arm. Move the object away from electroscope and electroscope charges will redistribute 'evenly' and rotating arm will return to original position.
- Charging by contact: Bring the object in contact with the top knob of the electroscope, charge can then transfer from object to the electroscope. Rotating arm deflects, the amount of deflection will depend on the amount of charge transferred. Remove object from electroscope and the arm should will remain deflected.
NOTE: If irregularities are observed in the interactions of the charged objects, it is recommended that all synthetic, including black carts, materials involved be rinsed off with water or wiped down with a wet cloth. Can also clean the top knob of electroscope with rubbing alcohol (oil from hands can build up on knob preventing charge transfer) - apply alcohol to clean cloth, rub all over knob then allow alcohol to evaporate.
Equipment:
Electroscope, Rods, Fur, & Silk kit
Location:
Shelf 313, 316 (the large electrscope on Shelf 331 does not work well)
Web Simulation:
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