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Physics: 12. Static Electricity
Please remember to photocopy 4 pages onto one sheet by going A3→A4 and using back to back on the
photocopier
Syllabus
OP48 Use simple materials to generate static electricity; demonstrate the force between charged objects
and the effects of earthing. Student Notes
When one object is rubbed against another, charges (electrons) often get transferred
from one object to the other.
Remember that electrons have a negative charge.
An object becomes positively charged if it loses electrons, and negatively charged if
it gains electrons.
Demonstration: using simple materials to generate static electricity
Option 1: Rub a biro (a balloon is even better) with a cloth to charge it and then use it to attract
pieces of tissue paper.
Option 2: A charged balloon can attract an empty coke can which is lying on a table.
Conclusion: Neutral objects are attracted to charged objects
To demonstrate the force between charged objects
1. Charge a plastic rod by rubbing it with a cloth and then hang it from a retort
stand.
2. Rub another rod with the same cloth (so that it will have the same charge) and
bring it up to the first rod.
Result:
The first rod will be repelled by the second rod.
Conclusion:
Similar charges repel.
Now bring up a different type of charged rod (which has an opposite charge).
Result:
The first rod will move towards the second rod.
Conclusion
Opposite charges attract.
A conductor is a substance that allows charge to flow through it easily (metals are conductors)
An insulator is a substance that does not allow charge to flow through it (plastics are insulators)
Similar charges repel; opposite charges attract
