There’s nothing funny about the ravages of highly addictive narcotics or gangland turf wars. Nevertheless, Vince Gilligan’s riveting hit Breaking Bad managed to start on a (yes, darkly) comic note that still sounds occasionally as the show hurtles toward its fateful conclusion this Sunday. (Conan O’Brien has had a lot of fun with these moments in parodies of the show’s characters’ quirks and its sometimes-gruesome desert absurdities.)

What anchors the show, even when it veers into gallows humor, is its sense of authenticity. Despite Breaking Bad’s theatrical—almost Shakespearean—plotting, Gilligan and his writers have taken care to build a very believable scaffolding behind every outrageous set piece, even when it comes to the science of perfectionistic chemistry teacher Walter White's super high-quality crystal methamphetamine. In order to get the science right, Gilligan approached Donna Nelson, Professor of Organic Chemistry at the University of Oklahoma.

Nelson doesn’t only consult on the nature of illicit chemical compounds; she has also provided the show’s writers with insights into the motivations and methods of chemists and teachers. As Nelson says, “to us who are educated in science, whenever we see science presented inaccurately, it’s like fingernails on a blackboard. It just drives us crazy, and we can’t stay immersed in the show.” As a Breaking Bad fan who is, I’ll be honest, largely chemistry-illiterate, I’d still credit some of my immersion to how real the science feels, a by-product, surely, of how genuine it is. Watch Professor Nelson in the video above, produced by the American Chemical Society, explain how the show created its illusions with the stuff of 100% real science.

Well, okay, it’s maybe more like 96%. As you might have suspected, the signature powder blue color of Walter’s product is pure dramatic invention.

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Josh Jones is a writer and musician based in Durham, NC. Follow him at @jdmagness