THE POWER OF MUSIC: After only a few months of study, young participants in the El Sistema music education program in Trenton were invited to play at a festival held last June at the New Jersey Performing Arts Center in Newark. The Trenton program is the focus of a Martin Luther King Day event at the Arts Council of Princeton, at which a documentary by Jamie Bernstein, daughter of composer Leonard Bernstein, will be screened.

One day eight years ago, Jamie Bernstein was casually scrolling through Facebook when she came upon a YouTube video titled Mambo: the Simon Bolivar Youth Orchestra. Since “Mambo” is one of the most famous compositions from the musical West Side Story, written by her late father, Leonard Bernstein, it caught her eye.

“I thought, okay, I’ll watch this for a second,” Ms. Bernstein recalls. “And I just about fell into my screen. I had never seen anything like it. The joy these kids had! I thought, who are they? And where is my Dad?”

In addition to being a world-famous composer and conductor, Leonard Bernstein was a social activist, passionate about engaging children in music. His daughter knows he would have been thrilled by El Sistema, the Venezuela-based music education initiative that is the source of the youth orchestra enthusiastically playing his music — at a raucous concert in London’s Royal Albert Hall — in the video.

Ms. Bernstein’s chance YouTube encounter was the beginning of a continuing relationship with the program, which was founded in 1975 and has since expanded from Caracas into cities all over the world. It would lead to the making of Crescendo, The Power of Music, a 2014 documentary about El Sistema programs in Philadelphia and Harlem that she co-produced and co-directed with filmmaker Elizabeth Kling.

Ms. Bernstein, a writer, speaker, and activist for music education, will be at the Arts Council of Princeton on Monday, January 18 for a screening of the film. The Martin Luther King Day event is an informational program about an El Sistema program in Trenton under the direction of the Trenton Community Music School. A brief performance by young musicians will precede the film.

“When I discovered this was taking place in impoverished neighborhoods, and that it was music for social justice, it was almost too good to be true,” Ms. Bernstein recalled during a telephone interview from her home just after Christmas. “I knew I had to go to Venezuela. So I bought a ticket and went with some friends.” She admits to feeling skeptical at first. “But I was bowled over,” she said. “I mean, this is a very tough neighborhood. And the people were fantastic. I met the founder, Jose Abreu, who I really think should get the Nobel Peace Prize.”

Ms. Bernstein was invited back to Caracas to narrate a concert about her father and the “Young People’s Concerts” series he led on prime time television during the late 1950’s. Having grown up in a bilingual household — her mother, late actress Felicia Monteleagre, was from Chile — she felt at home. “This brought everything together in my life in one incredible package,” she said.

Growing up Bernstein was “never boring … well, maybe sometimes,” she said. “But it was a fantastic experience. Our house was always full of people. There was a lot of laughter, a lot of word games being played, tennis being played, stories being told, and always music, of course. It was just a lot of fun.” Leonard Bernstein died in 1990 at the age of 72; his wife died in 1978 at age 56.

El Sistema has exploded since Ms. Bernstein began the process of making Crescendo six years ago. “There were three or four of these programs in the U.S. then, and now there are over 100,” she said. “Over half a million kids are enrolled right now in Venezuela, and it’s growing everywhere else.”

Music educator Jose Antonio Abreu founded the program 40 years ago in an underground parking garage, with a small group of children from a tough Caracas neighborhood. He was convinced that teaching underserved kids to play instruments and collaborate in an orchestra would instill in them discipline, harmony, solidarity, and mutual compassion, and consequently change their lives.

Among the most famous graduates of the program is Gustavo Dudamel, the music and artistic director of the Los Angeles Philharmonic and an enthusiastic proponent. “Music saved my life and has saved the lives of thousands of at risk children in Venezuela,” he has been quoted as saying. “Like food, like health care, like education, music has to be a right for every citizen.” Other success stories include a 19-year-old double bass player from Venezuela’s El Sistema who was recently hired by the Berlin Philharmonic. “That’s huge,” Ms. Bernstein said. “It’s one of the top orchestras in the world.”

But the aim of El Sistema isn’t to produce professional musicians. “The idea is about building human beings,” said Ms. Bernstein. “Some stay with music; others don’t.”

The film follows three children in two El Sistema-inspired youth orchestras, Harmony Project in Harlem and Play on Philly! in West Philadelphia. Viewers watch the children struggle to master their instruments and confront fears along the way, and see the surrounding community respond to the music. Making a documentary was new to Ms. Bernstein, but her friend Elizabeth Kling is a film editor and was confident they could make it happen. “If I had known what was involved, I probably wouldn’t have done it. So it’s good I didn’t know,” Ms. Bernstein said. “It was very hard. It was exhausting. We’re still pinching ourselves that we got it done.”

Ms. Bernstein grew to love the editing process that went into threading together the stories of young musicians in struggling neighborhoods. “It’s all about timing and rhythm, so maybe that has something to do with it,” she said. Since opening a year ago, Crescendo has won prizes and is now available on Netflix and I-Tunes. Screenings such as the January 18 event are a regular part of her schedule.

The Trenton Community Music School program was launched a year ago at Grant Elementary School. Less than a year after opening, the children performed at the New Jersey Performing Arts Center as part of the NJ El Sistema Alliance, and as special guests of the Princeton Symphony Orchestra in last month’s Holiday POPS! concert.

So how would Leonard Bernstein have reacted to El Sistema? “That’s all I ever think about,” Ms. Bernstein said. “How thrilled he would have been! He was so committed to making the world a better place. He didn’t live long enough to see that there was this program that put together the elements he cared most about. It’s kind of what impelled me to make the film. It was like I was telling his story.”

The screening of Crescendo: The Power of Music is Monday, January 18 at 7 p.m. at the Arts Council of Princeton, 102 Witherspoon Street. The film will be preceded by a brief performance by Wood N Strings, a youthful Trenton-based string quartet, and followed with a reception with Ms. Bernstein and Stanford Thompson, teaching artist and founder of Play on Philly!, featured in the film. Admission is free but seating is limited and reservations are strongly suggested: email info@trentoncommunitymusic.org.