Why did the Zap Tester work?

When you touched the Zap Tester to different objects, some made the LED light up while others did nothing.

The difference comes down to whether electricity can move through the material.

For the LED to light, electricity needs a complete pathway from the battery, through the test object and LED, and back to the battery. This complete pathway is called a circuit.

If there is a break anywhere in the circuit, the electricity cannot travel all the way around and the LED stays off.

What are conductors and insulators?

Some materials allow electricity to move through them easily. These are called electrical conductors.

Metals such as copper, aluminium and steel are usually good conductors. Inside metals, some electrons are able to move through the material more easily, allowing electrical energy to travel through the circuit.

Other materials make it much harder for electricity to move. These are called electrical insulators.

Materials such as plastic, rubber, glass and dry wood are usually good insulators.

This is why electrical wires often have metal on the inside and plastic on the outside. The metal carries the electricity while the plastic helps keep us safe.

What did your Zap Tester discover?

Your Zap Tester turned each object into part of the circuit.

When you tested a conductor, electricity could travel through the object and complete the circuit. The LED lit up.

When you tested an insulator, the pathway was interrupted and the LED stayed off.

That means the LED wasn't just a light — it was giving you evidence about the material you were testing.

By testing different objects and comparing the results, you were using evidence to classify materials as conductors or insulators.

Curiosity Spark

Electrical conductors and insulators are hidden inside almost every electrical device around you.

Phone chargers, computers, appliances, power cords and even electric cars need materials that allow electricity to travel exactly where engineers want it to go — while stopping it from travelling where it shouldn't.

But not everything fits neatly into "conductor" or "insulator."

Even water can conduct electricity differently depending on what is dissolved in it.

So here's your next mystery:

Could you use your Zap Tester to compare which liquids conduct electricity best?

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