💡 Where Does Electricity Go?

Hello! How do we light a bulb? Which way does electricity travel from the cell to the bulb? Some materials let electricity pass through and some don’t. Today we are going to find out!

A simple electrical circuit is made of four parts. The cell gives the energy. The wire makes the path. The bulb gives light. The switch opens and closes the circuit.

Electric current leaves one end of the cell, passes through the wires and the bulb, and goes back to the other end of the cell. The path must be a complete loop from start to finish. This is called a closed circuit. When the switch is open, the path is broken and the bulb doesn’t light. Close the switch and the bulb lights up!

Now let’s leave a gap in the circuit. The path is broken, so the bulb doesn’t light. Let’s put a metal spoon in the gap: the bulb lights up! The metal spoon let the current pass through. Materials like this are called conductors.

Let’s put rubber, wood and plastic in the same gap. The bulb doesn’t light, because these materials don’t let current through. Materials like this are called insulators. Metals are good conductors. Rubber, wood and plastic are insulators.

Let’s sum up. Conductors let electricity pass through: metals such as a spoon, a bolt and a coin. Insulators don’t let electricity pass through: things like wood, plastic and rubber.

Electric cables have copper inside, because copper is a good conductor. The outside is plastic, because plastic is an insulator. The plastic coating stops the current from passing to us or to other wires.

A very important warning! Plug sockets and mains cables at home are very dangerous. Never push anything into a socket and never touch a bare wire. We only do our experiments with a cell, and with a grown-up.

The longer and thinner a wire is, the greater its resistance to the current. When the resistance is big, the current gets smaller and the bulb shines dimly. In a short, thick wire the resistance is small and the bulb shines brightly. A variable resistor is a part that lets us change the resistance.

Summary: current flows round a closed circuit. Conductors let current pass through and insulators don’t. A long, thin wire increases the resistance, and the bulb gets dimmer. Never touch sockets or bare wires! Now try it in Matter and Circuits!