In Brief
Quantum mechanics is a wildly powerful and complex branch of physics in which its particles behave in sometimes unexplained and strange ways. A video from the University of New South Wales discussed some of these processes in the everyday occurrence of turning on a light.

The Quantum World Around You

We generally think of the quantum world as something completely separate from the world we see and interact with. I guess you, in a manner of speaking, you could say that this line of thinking isn’t far from the truth, but, in fact, they are the same world…just with drastically different rules.

With that said, if you open your mind to it, there is a whole dynamic host of things, quantum things, happening all around you. Sure, many of you have heard of such phenomena: like electron repulsion — a principle that essentially tells us that the electrons in our bodies push against the electrons in everything we come in contact with, and they prevent us from ever truly touching anything — the van der Waals force, which explains how geckos can scale walls, and even the most basic forms of magnetism.

In a new episode of “The Quantum Around You” — a truly exceptional youtube channel launched by the University of New South Wales (UNSW) — Andrea Morello, the Associate Professor of the School of Electrical Engineering and Telecommunications at UNSW, discusses the quantum effects that stem from flipping a light switch.

From Wires to Waves

As explained by ScienceAlert:

“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. This phenomenon makes the wire stop acting like a wire, and more like a quantum mechanical wave guider.”

“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.”