Electricity and Circuits

Electricity is a flow of tiny particles called electrons moving through a material. We use electricity for almost everything — lighting our homes, powering computers, charging phones and running trains. It is one of the most useful forms of energy we have.

Some materials let electricity flow through them easily. These are called conductors, and most metals — especially copper — are excellent conductors. That is why electric wires are made of copper. Materials that do not let electricity flow are called insulators, such as plastic, rubber and glass. Wires are coated in plastic to keep us safe.

A simple circuit has a few main parts: a power source such as a battery, wires to carry the current, a load such as a bulb or buzzer that uses the energy, and usually a switch to turn it on and off. The battery acts like a pump, pushing the electrons around the loop.

A switch is simply a clever gap in the circuit. When the switch is open, there is a break in the loop, so no electricity flows and the bulb is off. When you close the switch, the gap is bridged, the loop is complete, and the electricity flows again to light the bulb.

Scientists describe electricity using two important measurements. Voltage, measured in volts (V), is the push that drives the current around the circuit. Current, measured in amperes or amps (A), is how much electricity flows each second. Adding more voltage usually makes a bulb shine brighter or a motor spin faster.