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Q & A: Experiment with charged objects

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Most recent answer: 10/22/2007
Q:
If you had to set-up an experiment that involved two electrically charged particles, what could you use (that’s big enough to see) for the particles? How can you get the objects charged and how long will they stay that way? Thanks!
- Courtland (age 15)
A:
Hi Courtland,

Some suggestions for practical demonstrations:

1) Try rubbing an inflated balloon on your hair (it works better if it is recently washed and dry). The balloon and your hair will then charge up and attract each other. The balloon will also stick to most walls because of electrostatic forces. The discharge time depends on the humidity of the air and if any contact is made with an object which can conduct away the electricity.

2) Styrofoam balls make good carriers of static electricity. Try rubbing them on hair or cloth or rubber or other things to try to charge them up. Same story with discharging.

3) Electrons are useful, but take some equipment to manipulate. A TV picture tube throws electrons at a phosphorescent surface. Some TV picture tubes and computer monitors will develop a static charge on their outer glass surface, which is often more noticeable when the monitor is turned on or off.

4) You can also detect static electric charge with a leaf electroscope. This consists of a jar with dry air in it, with a conducting rod going through the lid, attached to two thin pieces of metal which can bend easily. Aluminum foil might work, but most aluminum foil is too stiff to bend in the small forces. One design I found hangs the little leaves of alumninum foil on a loop of copper wire hung from the conducting rod.

Try experimenting!

Tom

(published on 10/22/2007)

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