If you grew up with VHS tapes, you probably remember from elementary school the excitement of a rainy day or one of those days your teacher wasn’t feeling well.

“Then the cart would come in and you’d just hear, ‘BILL! BILL! BILL! BILL!’” a now-grown up fan recalled in the film, "Bill Nye: Science Guy."

That fan was one of the 20-somethings who, at the start of the film, is seen filling a venue where Bill Nye is set to speak. The energy and nostalgia was palpable through the Alamo Drafthouse screen at the film’s world premiere during South by Southwest.

The camera then takes you backstage, where a graying Nye looks into a mirror at the wrinkled hands that slowly fiddle with his bow tie.

And when he walks on stage, he’s greeted with screams from both children and young adults who grew up with him.

Later in the film, as he walks through a convention, he’s followed by swarms of grown up kids armed with iPhones and asking for selfies.

“I’ve been asked to talk about selfie fatigue,” Nye said in the movie. “I’m pretty sure it shortens your life.”

The film then cuts to him taking selfie after selfie with fans, giving the same open-mouthed expression your grandpa probably makes.

He’s a good sport, and it’s probably due to the fact that he’s aware of the impact he’s had.

Before he began filming “Bill Nye the Science Guy,” Nye asked for advice from the man he’s always looked up to: Carl Sagan. The original face of “Cosmos” – before Neil DeGrasse Tyson took over – and Nye’s astronomy professor at Cornell University, Sagan had a way of making science fun and understandable.

“’You should focus on pure science,’” Nye recalled from Sagan’s advice. “’Kids resonate with science.’”

While the film shows Nye setting out to fulfill Sagan’s dream of launching a spacecraft that could revolutionize interplanetary exploration, he is repeatedly finding himself going head-to-head with climate change and evolution deniers such as meteorologist Joe Bastardi and creationist Ken Ham.

One of the points brought up in the film is that by engaging and debating with people who spew false claims about climate change and evolution, Nye is giving them a platform and may actually be helping their cause. The filmmakers addressed this after the film screening.

“This is something we need to engage directly because you have to be able to stand up to ideas and let facts prevail,” director Jason Sussberg said.

Sussberg said he and co-director David Alvarado made a point of not alienating people based on their religion.

“Both David and I grew up religious, so that was one of the elements that we wanted to bring into the movie,” Sussberg said. “You don’t have a Christian science and a Muslim science and an atheist science. It’s just science. So it was important to us to not have it stand in opposition to religion.”

“Bill Nye: Science Guy” also shines a light on the imperfections that plague the engineer-turned-celebrity’s personal life.

A long-time friend of his tells the filmmakers he met the science guy when he took part in a Steve Martin look-alike contest. (Which, based on footage of that fierce competition, he better have won.)

His friend went on to say that Nye has always wanted to – perhaps more than anything – be famous.

Nye admits that his fame has closed him off.

The filmmakers captured an interview between Nye and a scientist looking at the effect of fame on the psyche. She asks him about why he never had a family or kids.

Turning nearly every question into a joke, he begins to act like a child himself.

“Well, this is it,” Nye told her, talking about his career. “Dude?! Dude.”

Another reason he said he made the decision to not have kids is due to a condition that runs in his family. His brother and sister who are afflicted with the condition have a hard time seeing and walking around.

Near the end of the film, Nye talks about his mother, a codebreaker during World War II, and his father, a prisoner of war. At one point Nye tells the camera that his father always told him to leave the world better than he found it.

“Yeah, I’ve made mistakes,” Nye said. “But I’m proud of my legacy. I’m just trying to change the world here.”