Physical Science / Unit 10: Electricity and Magnetism
10.1 Electric Charge
Notes
Matter contains positive protons and negative electrons. Objects become charged by gaining or losing electrons.
- Like charges repel; opposite charges attract.
- Static electricity is a buildup of charge on an object. Charging methods: friction, contact (conduction) and induction.
- Only electrons move. An object that gains electrons becomes negative; one that loses electrons becomes positive.
- Conductors (metals) let charge flow easily. Insulators (rubber, plastic, glass) do not.
- Charge is conserved: it is transferred, not created. Lightning is a rapid discharge of static electricity.
Practice
Two objects both have a negative charge. They will:
Like charges repel.
A balloon rubbed on hair becomes negative. What happened?
Only electrons transfer between objects.
Which material is the best insulator?
Rubber does not let charge move freely.
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