Think quantum phenomena only occur in high-tech physics experiments or on the nanoscale? Actually, they happen every time you switch off a light. 

Electrical wires are made of metal, which means they're great at carrying an electrical current. But when you make that wire really small, the wires start to exhibit quantum conductance.

As the latest episode of The Quantum Around You from Australia's University of New South Wales (UNSW) eLearning channel explains, this phenomenon makes the wire stop acting like a wire, and more like a quantum mechanical wave guider. 

Hosted by quantum guru Associate Professor Andrea Morello from the School of Electrical Engineering and Telecommunications at UNSW, the new video explains that this is because at some point the electrons that make up a current aren't the billiard balls they're portrayed as in simple diagrams, they're actually quantum mechanical waves. And when the wire gets small enough at some point it'll reach a limit where it's the same width as the waves travelling within it, which means that the conductance can now be measured in quanta.

You might think that you'd never use a wire this small in any of today's technology, but you actually create one every time you turn off a light. This is because a light switch has two metal plates stuck together when it's "on", and these are pulled apart when you turn it off. But this pulling apart doesn't occur instantaneously - at some point the contact surface between the two plates becomes extremely small, and if you zoom in closely, atom-width wires form.

But trust us, it makes a lot more sense when Andrea explains it. Watch the video above to find out more about how quantum conductance occurs every night when you go to bed.

Source: UNSW eLearning