What is Static Electricity?
A build-up of electric charge on the surface of an object, which remains stationary (static) rather than flowing as a current.
You have almost certainly experienced static electricity without realising it had a name. That shock you get touching a metal door handle after walking across a carpet? Static electricity. The way a balloon sticks to a wall after rubbing it on your hair? Also static electricity. The crackle and spark when you pull a jumper over your head in a dark room? You guessed it — static electricity.
Unlike current electricity, where charges move continuously around a circuit, static electricity involves charges that build up in one place. The word static means stationary or not moving, which tells you exactly what is happening — the charges sit on the surface of an object until they get a chance to discharge.
Think of static electricity like filling a bucket with water. You keep pouring water in (building up charge) until the bucket overflows (discharge). Current electricity, by contrast, is like water flowing continuously through a pipe.
This subtopic connects directly to our unit question — Are Our Futures Electric? Understanding how charge builds up, moves, and discharges is the foundation for technologies ranging from air filters in factories to the printers in your school — and for understanding the hazards we need to manage in an increasingly electrified world.
Atoms, Electrons and Charge
To understand static electricity, we need to revisit atomic structure. All matter is made of atoms, and atoms contain three types of subatomic particles:
| Particle | Location | Relative Charge | Relative Mass |
|---|---|---|---|
| Proton | Nucleus | +1 | 1 |
| Neutron | Nucleus | 0 | 1 |
| Electron | Shells around nucleus | −1 | negligible (≈ 1/1836) |
Relative mass here means mass compared to a proton. Protons and neutrons each have a relative mass of 1. Electrons are so much lighter — about 1/1836 of a proton — that their mass is considered negligible in most calculations.
The key points for static electricity are:
- Protons and neutrons are fixed in the nucleus — they do not move between atoms under normal conditions.
- Electrons are on the outer shells of atoms and can be transferred from one material to another when surfaces are rubbed together.
- A neutral (uncharged) atom has equal numbers of protons and electrons, so the charges cancel out.
A fundamental property of matter. Positive charge is carried by protons; negative charge is carried by electrons. Like charges repel; opposite charges attract.
Only electrons move when objects become charged by friction. Protons never leave the nucleus in electrostatic situations. This is a very important point that many students misunderstand.
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