Some four decades ago,Liz Keimwas between San Francisco apartments, couch surfing as she looked for another rental. She needed somewhere to stash her furniture, and the place where she worked, the Exploratorium, had ample storage space.

Not long afterward, Keim was walking through the museum — then located at the Palace of Fine Arts — and noticed a new exhibit: It was a coupled pendulum experiment, in which swinging one linked pendulum can get the other one going, a simple demonstration of energy transference.

And it had been nailed to her kitchen table.

“The guys in the machine shop knew it was mine because of the parties that I used to host at my flat,” Keim recalled of the modest table, perfect for tiny San Francisco apartments. “But by then Frank had rolled it out of the rotunda. I didn’t get it back.”

The Frank she’s referring to, of course, was Frank Oppenheimer, the charismatic founder ofthe Exploratorium— the science, technology and arts museum that opened in 1969. Though Oppenheimerdied in 1985,and the museum is a decade into its current location at Pier 15, the coupled pendulum experiment is still on display — and still attached to Keim’s old table.

“Oppenheimer,”visionary directorChristopher Nolan’sthree-hour epic about the Manhattan Project that developed the first atomic bomb during World War II, is bringing renewed interest aboutJ. Robert Oppenheimer,Lawrence Berkeley National Laboratoryscientist who is often called “the father of the atomic bomb.”

But the film, set for release Friday, July 21, is also shining new light, at least in these parts, on Frank Oppenheimer — a brilliant physicist in his own right who also worked in Berkeley and was a part of his older brother’s team in Los Alamos, N.M. — andthe museum in San Franciscothat has become his lasting legacy.

罗伯特我s played by established star Cillian Murphy (“Peaky Blinders”), while Frank is played by Dylan Arnold, an up-and-coming actor who appeared in the recent “Halloween” and “After” films.

在一次电话采访前的编年史SAG-AFTRA strike was called, Arnold said he prepared for the role by watching archival interviews with Frank and reading“Something Incredibly Wonderful Happens: Frank Oppenheimer and His Astonishing Exploratorium”by K.C. Cole, as well as the Pulitzer Prize-winning“American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer”by Kai Bird and Martin J. Sherwin.

And he drew on a personal experience from youth.

“I went to the Exploratorium when I was very young, when it was still in the old building,” recalled Arnold, who grew up in Seattle but often visited his grandmother, Jan, who lives in Marin County. “I remember running around the giant warehouse-like room and just wanting to touch everything, which I’m sure Frank would have appreciated.

“I think I’m like Frank in that way where I want to touch and explore. My dad would always say that I was a kinesthetic learner. I needed to touch things to figure them out.”

Another boy who visited the Exploratorium was Charles Oppenheimer, grandson of J. Robert Oppenheimer, though Charles got to know his great-uncle Frank more from Frank’s visits to the New Mexico ranch where he grew up, which is still in the family.

“He was really friendly; as a kid he was easy to talk to,” recalled Charles, who has been a San Francisco resident for 25 years. “One distinct memory I have is we were up at the ranch in New Mexico, and he went up to this spring and he took off his hat and filled up his hat and drank out of his hat. I found that shocking. I’m like, ‘That’s not how you drink out of the spring. You’re supposed to lie down and take it.”

Keim, who began as a weekend receptionist, and scientistRob Semperwere both hired by Frank Oppenheimer in 1977, and found their life’s work at the Exploratorium. Keim is now the director of cinema arts and senior curator; Semper is chief learning officer.

Each recalled being captivated by Frank’s relentless curiosity and his egalitarian nature.

“He was an intensely curious person,” Semper said. “He was interested in anything and everything, and when you worked with him,youbecame interested in everything as well. That was one of the joys of getting to work closely with him over the years.

“He had very little pretension,” Semper continued. “He would talk to anybody — whether it would be an eminent physicist coming to visit, or a high school program of people on the floor — about physics, or about life, or about things he was discovering, or philosophy or social issues. I found that to be incredibly invigorating and exciting.”

Keim, who applied when she was a graduate student at San Francisco State University, remembers just wanting a summer job when she showed up to be interviewed by Frank.

“Everyone’s in blue jeans and T-shirts and in their 20s, and then here comes this elderly gentleman dressed in a suit with a tie,” Keim said. “I had no idea who he was, but he came in and we had one of those conversations that just intrigued me. The musing that we did; there was just something about him, and I realized I wanted the job.”

当他回忆起弗兰克的永远笑了ubiquitous tie.

“He wore a suit and tie in the machine shop where we’re building these exhibits, you worried about him getting his tie caught up in the apparatus and machinery,” Semper said. “He came from an era when scientists actually dressed up to go to the lab.”

Keim also remembered that Frank loved to surround himself with younger people, believing that it was key to keeping the museum in a perpetual sense of renewal. To this day, the Exploratorium bills itself not as a museum, but as “a public learning laboratory where you can explore the world through science, art, and human perception.”

“Frank handled cacophony in a way that a lot of people don’t,” Keim said. “He did not want any signs in the museum that said what the rules were. There were bicycles, there were dogs, there was whatever. He would say, ‘If you keep repeating your successes, you’re going to fail.’ ”

Charles Oppenheimer, who has started the nonprofitOppenheimer Projectto promote the thoughts, value and leadership example of J. Robert Oppenheimer as well as his “vision of international cooperation and increased unity to address existential threats that arise from the growth of science and technology,” said the Exploratorium is the lasting legacy of his great-uncle.

“Frank being an experimentalist and a builder and loving the teaching of science and building up a lasting institution is so relatable,” Charles said. “The Exploratorium is amazing, and his legacy is literally immeasurable. Countless kids have experienced the science that he created.”

Some have suggested that Frank Oppenheimer, who also spent time as a cattle rancher and high school teacher in Colorado when he was blacklisted from teaching at universities in the 1950s, started the Exploratorium as a way to atone for his part in inventing the atomic bomb.

Semper doesn’t subscribe to that notion.

“I never got a sense of that,” he said. “I think it is really critical to understand what the world was like and what people were responding to at the time.”

Keim, however, speculated that Frank did indeed feel remorse.

“I think that’s why the Exploratorium had so much of his vision about a healthy world,” she posited, “just in terms of us understanding science, which is under threat now, and how to work with communities and go beyond just your own self. All of that in his conversations and the way he designed this museum is evidence.”

Oh, and that table? Keim said she eventually got a replacement.

“When I found an apartment, Frank gave me one of his old kitchen tables,” she said with a laugh. “We figured out that it came from the ranch in Colorado.”

Reach G. Allen Johnson:ajohnson@sfchronicle.com;Twitter: @BRfilmsAllen