What is Quantum Mechanics?

Live Science

Astrophysicist Paul Sutter explains Quantum Mechanics - the body of scientific laws that describe the wacky behavior of photons, electrons and the other particles that make up the universe.

Transcript

00:00Quantum mechanics is our fundamental framework for understanding the physics,

00:06the behavior of the very, very small. I'm talking like atoms, molecules, and

00:12subatomic particles. I'm Paul Sutter and this is Paul Explains, the show where I,

00:19you know, explain. There's three big pieces to quantum mechanics. One of the

00:27pieces is in the name itself, this idea of quantization, that certain properties

00:35of subatomic systems like energy or angular momentum come in discrete levels

00:44or packets or what we call quanta, hence the name quantization. For example, an

00:50electron in an atom can't have any old energy that it feels like. No, it can have

00:58only certain energy levels. That's because the energy levels in an atom are

01:03quantized. This is a fundamental core tenant of quantum mechanics and it's

01:08very different than the physics of the macroscopic world. Another key component

01:14of quantum mechanics is something we call wave-particle duality, where tiny

01:19things sometimes act like particles, like tiny little bullets, tiny little

01:25billiard balls, tiny little ping-pong balls bouncing around doing everything

01:28that particles do, and sometimes also act like waves where they're more sloshing

01:36around or they interfere with each other. Depending on what you're looking for and

01:42how you're looking for it, sometimes, sometimes it might act like a little bit

01:46of both. And the last bit is that quantum mechanics and subatomic systems are

01:52ruled by probabilities and uncertainty. Up here in the macroscopic world, if you

01:59can know exactly where something is and exactly how fast it's moving and you can

02:04predict, using the laws of physics, exactly where it's gonna be, exactly

02:09where it's gonna go, but you don't get that kind of precise knowledge in the

02:15subatomic world. You don't always know exactly where something is, like an

02:20electron. You don't always know where an electron is or how fast it's going. And

02:24once you do know where it is, or at least have some idea, you don't know exactly

02:30where it's gonna go. Instead, it's gonna be a range of probabilities. Our

02:36understanding of quantum mechanics underlies so many things. Atomic and

02:43nuclear power, all of that is thanks to our understanding of quantum mechanics.

02:47Microchips, semiconductors, lasers, and LED, and even biology. So, you know, a bunch of

02:55physicists playing around in the early 20th century gave us this major

03:00cornerstone of many fields of science.

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