Last reviewed: 25 October 2026
Electricity is a topic learners meet in upper primary Science and Technology and build on in junior school Integrated Science. Questions test whether a learner can read a circuit diagram, predict whether a bulb will light and explain how to stay safe. This guide covers each of these with clear explanations.
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Sources of Electricity
Electricity can come from dry cells (batteries), solar panels, generators and the national grid. In Kenya, much grid electricity is generated from geothermal, hydro and wind sources, along with others. Dry cells and solar panels produce direct current (DC), while mains electricity at home is alternating current (AC). Batteries store chemical energy and change it into electrical energy.
A Simple Circuit
A circuit is a complete path that electric current flows around. A simple circuit needs:
- a source, such as a cell;
- connecting wires;
- a load, such as a bulb or buzzer, that uses the energy;
- usually a switch to open or close the circuit.
If there is any gap in the path, such as an open switch, a loose wire or a broken bulb filament, current stops and the bulb goes off. Exam questions often show several circuits and ask which bulb lights. Trace the path with your finger from one end of the cell to the other; if you can complete the loop through the bulb, it lights.
Circuit Symbols
Scientists use standard symbols so diagrams are quick to draw and easy to read. Learners should recognise the symbols for a cell (a long and a short line), a battery of cells, an open and closed switch, a bulb (a circle with a cross), a wire, a resistor (a rectangle) and an ammeter (a circle with A). Draw wires as straight lines with a ruler.
Series and Parallel Circuits
In a series circuit, components are connected one after another in a single loop. The same current flows through each. If one bulb breaks, all the others go off. Adding more bulbs in series makes each one dimmer.
In a parallel circuit, components are on separate branches. If one bulb breaks, the others stay on, and each bulb glows about as brightly as a single bulb would. Homes are wired in parallel, which is why switching off one light does not switch off the rest.
Conductors and Insulators
Conductors let electricity flow through them easily. Metals such as copper, aluminium and iron are good conductors, which is why wires are made of copper. Graphite (pencil lead) also conducts. Insulators do not allow electricity to flow. Plastic, rubber, dry wood, glass and cloth are insulators, which is why wires are coated in plastic and electricians use rubber-handled tools.
A classic experiment connects different materials into a gap in a circuit. If the bulb lights, the material is a conductor; if it does not, it is an insulator. Learners should be able to describe this experiment and record results in a table.
Electrical Safety
- Never touch switches or sockets with wet hands; water conducts electricity.
- Do not overload sockets with many appliances.
- Do not poke objects into sockets.
- Replace frayed or broken cables.
- Keep away from fallen power lines and report them to the electricity provider.
- Switch off and unplug appliances before cleaning them.
Fuses and circuit breakers protect homes by cutting off current if too much flows, preventing fires.
Saving Electricity
Switching off lights in empty rooms, using energy-saving bulbs and unplugging chargers all reduce bills and waste. Questions sometimes ask for three ways to save electricity at home or school.
Revision Plan
Draw three circuits from memory: a simple circuit, a series circuit with two bulbs and a parallel circuit with two bulbs. Label every component. Then practise with the Grade 7 Integrated Science papers or the Grade 5 Science and Technology papers. The exam countdown gives free daily questions and the What to Revise report highlights weak areas. Full papers with answers come with the Monthly Pass (KSh 500 by M-Pesa).