Unit 9: Electricity and circuits
The flow of electricity — HIA International - Grade 6 Revision Notes & Topical Questions
5 min read 8 parts Lesson 2 of 16 2 quizzes
Lesson summary
9.1 The flow of electricity — HIA INTERNATIONAL notes: Describe electric current as the flow of electrons around a complete circuit.Cell = a store of chemical energy that is changed to electrical energy in a circuit.Battery = two or more cells joined together.Terminals — a cell, …
- Pushing electrons
- Free electrons
- Without a circuit
- Opposite charges attract
- Like charges repel
- Electron direction
Part 1 of 6Cells and batteries
Cell
Cell a store of chemical energy that is changed to electrical energy in a circuit.
Battery
Battery two or more cells joined together.
Terminals
- Terminals a cell, battery or power supply has two connections, labelled + (positive) and − (negative).
Pushing electrons
- Pushing electrons the negative terminal pushes electrons around the wires.
Part 2 of 6Current
Electron
Electron a small negatively charged particle inside an atom.
Current
Current the flow of electrons around a circuit.
Complete circuit
- Complete circuit current flows only if there is an unbroken loop, and a break stops all the electrons.
Unit
- Unit current is measured in amps (A) with an ammeter.
Part 3 of 6Electrons in a metal
Free electrons
- Free electrons some electrons in a metal are free to move through it.
Without a circuit
- Without a circuit the free electrons move randomly in all directions.
In a circuit
- In a circuit the electrons all move in the same direction.
Size
- Size electrons are very small particles.
Part 4 of 6Charges and direction of flow
1Opposite charges attract
- Opposite charges attract a positive and a negative charge pull together.
2Like charges repel
- Like charges repel two positive or two negative charges push apart.
3Electron direction
- Electron direction electrons are attracted to the positive terminal and repelled from the negative terminal, so they flow from − to +.
4Conventional current
- Conventional current drawn from + to −, the opposite direction to the electrons.
Part 5 of 6Energy and current
Not used up
- Not used up the electrons are not used up as they go round; energy is transferred to components.
Same everywhere
- Same everywhere in a series circuit the current is the same all the way round.
All lamps together
- All lamps together lamps far from the cell light at the same moment as lamps near it,
- because the electrons are already in the wires and all start moving at once.
Part 6 of 6String loop model of a circuit
1
Tie a long string into a loop and mark it at equal intervals.
2
Stand in a circle, each holding the loop in both hands.
3
One person acts as the cell and pulls the string through the other people's hands.
4
The others act as components such as lamps or buzzers.
What the string shows
- What the string shows the marks represent electrons, and all parts of the loop move at the same time.
Limitation
- Limitation the string model does not show electrons as charged particles or their attraction to the positive terminal.
Key terms
| Term | Meaning |
|---|---|
| Cell | A store of chemical energy used to push current. |
| Battery | Two or more cells joined together. |
| Terminal | A connection point on a cell or battery. |
| Electron | A small negatively charged particle in an atom. |
| Current | The flow of electrons around a circuit. |
| Attract | To pull together. |
| Repel | To push apart. |
| Free to move | Able to move through a material. |
Avoid these mistakes
1
Saying current is used up — electrons keep flowing and energy is transferred.
2
Saying electrons flow from + to − — electrons move from the negative terminal to the positive terminal.
3
Thinking electrons only move in the part of a circuit near the cell — they move everywhere at the same time.
4
Saying atoms flow round a circuit — electrons flow.
Marked practiceQuizzes for this lesson
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