Electricity Revision Notes (Years 4–8)
1. Introduction to Electricity (Year 4–5)
� What is Electricity?
- A form of energy caused by the movement of electrons.
- Powers things like lights, computers, and TVs.
⚡ Types of Electricity
- Static Electricity – caused by rubbing (e.g., rubbing a balloon on your hair).
- Current Electricity – flows in wires and powers devices.
� Electrical Sources
- Cells (Batteries): Portable sources of electricity.
- Mains Electricity: Comes from power stations, used in homes and schools.
� Basic Components
- Cell – provides energy.
- Wires – conduct electricity.
- Bulb – lights up when electricity flows.
- Switch – opens or closes a circuit.
Topical Questions:
1. What’s the difference between static and current electricity?
2. Draw a simple circuit with a cell, bulb, and a switch.
3. What happens when you open a switch in a circuit?
2. Simple Circuits (Year 5–6)
� Complete Circuits
- Electricity only flows in a complete (closed) circuit.
- Open circuit: Switch is off – no flow.
- Closed circuit: Switch is on – flow occurs.
� Series Circuit
- All components are in one loop.
- If one bulb goes out, all others go out too.
� Parallel Circuit
- Components are on separate branches.
- If one bulb goes out, others stay on.
� Conductors vs Insulators
- Conductors: Allow electricity (e.g., metals).
- Insulators: Don’t allow electricity (e.g., plastic, rubber).
Topical Questions:
1. What is a series circuit? Give an example.
2. Name two conductors and two insulators.
3. Why does a bulb go off in a series circuit if another one breaks?
3. Electrical Safety (Year 6)
⚠️ Key Safety Rules:
- Never touch plugs or wires with wet hands.
- Don’t overload sockets.
- Keep water away from electrical devices.
⚠️ Fuses and Circuit Breakers
- Protect you from too much current.
- A fuse breaks the circuit if current is too high.
Topical Questions:
1. Why is water dangerous near electricity?
2. What is the purpose of a fuse?
3. Give two rules for staying safe with electricity.
4. Measuring Electricity (Year 7–8)
⚠️ Electrical Quantities
- Voltage (V) – Push of electricity (measured in volts).
- Current (I) – Flow of electricity (measured in amperes or amps).
- Resistance (R) – Opposition to flow (measured in ohms).
⚠️ Ohm’s Law
-V=I×R
� Measuring Instruments
- Voltmeter – measures voltage.
- Ammeter – measures current.
� Series vs Parallel (Advanced)
- Series: Current is the same; voltage is shared.
- Parallel: Voltage is the same; current is shared.
Topical Questions:
1. State Ohm’s Law.
2. In a series circuit, what happens to the current?
3. What instrument is used to measure voltage?
5. Practical Applications (Year 8)
� Everyday Devices
- Appliances convert electrical energy to other forms (light, sound, heat).
� Energy Efficiency
- Energy-saving bulbs use less electricity.
- Look for energy ratings on devices.
� Renewable vs Non-Renewable Sources
- Renewable: Solar, wind, hydro.
- Non-Renewable: Coal, oil, gas.
Topical Questions:
1. Give two renewable sources of electricity.
2. How does a kettle use electricity?
3. Why are energy-efficient devices better?
Circuit Diagrams
Series Circuit:
Parallel Circuit:
Basic Components of a Circuit:
- Cell: Provides energy (symbol: |‾|).
- Wire: Connects components (symbol: ——).
- Bulb: Converts electrical energy to light (symbol: ⊗).
- Switch: Opens/closes circuit (symbol: •/ ◦ ).
Electricity Practice Worksheets
Worksheet 1: Circuit Symbols and Components
Match the circuit symbols with their correct names:
1. ⊗
a) Switch
2. |‾|
b) Cell
3. ——
c) Wire
4. •/◦
d) Bulb
Answers:
1. __ 2. __ 3. __ 4. __
Worksheet 2: Series and Parallel Circuits
1. In a series circuit, what happens if one bulb breaks?
2. In a parallel circuit, why do other bulbs stay on if one breaks?
3. Draw a simple series circuit with a battery, two bulbs, and a switch.
4. Draw a simple parallel circuit with two bulbs and a battery.
Worksheet 3: Electricity in Daily Life
1. List five devices at home that use electricity.
2. Which of them convert electricity into:
- Light: __________
- Heat: __________
- Sound: __________
3. Name two safety rules when handling electrical appliances.
Worksheet 4: Electrical Calculations (Year 7–8)
Use the formula: V = I × R
1. A current of 2 A flows through a resistor of 5 ohms. What is the voltage?
2. A circuit has a voltage of 12 V and resistance of 6 ohms. What is the current?
3. A current of 3 A flows when the voltage is 9 V. What is the resistance?
4. Which instrument would you use to measure current? __________
5. Which instrument would you use to measure voltage? __________