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

00:57have only 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 very

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

01:13component of quantum mechanics is something we call wave particle duality,

01:17where tiny things sometimes act like particles, like tiny little bullets, tiny

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

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

01:35sloshing around or they interfere with each other. Depending on what you're looking

01:41for and how you're looking for it, sometimes, sometimes it might act like a little bit of both.

01:47And the last bit is that quantum mechanics and subatomic systems are ruled by probabilities

01:54and uncertainty. Up here in the macroscopic world, if you can know exactly where

02:01something is and exactly how fast it's moving and you can predict, using the laws

02:05of physics, exactly where it's gonna be, exactly where it's gonna go, but you don't

02:11get that kind of precise knowledge in the subatomic world. You don't always know

02:18exactly where something is, like an electron. You don't always know where an

02:21electron is or how fast it's going. And once you do know where it is, or at least

02:28have some idea, you don't know exactly where it's gonna go. Instead, it's gonna be a

02:33range of probabilities. Our understanding of quantum mechanics underlies so many

02:41things. Atomic and nuclear power, all of that is thanks to our understanding of

02:46quantum mechanics. Microchips, 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 cornerstone of

03:01many fields of science.

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