SELINSGROVE — Rodgers and Hammerstein’s beloved musical, “The Sound of Music,” opens tonight at 8 p.m. in the Degenstein Center Theater on the campus of Susquehanna University, with seven performances over the next week.

“It has universal appeal,” said W. Douglas Powers, associate professor of theater, who is directing the show.

“Everyone has seen the movie and knows the music,” Powers continued, “but the stage performance is different. There are four songs that aren’t in the movie, for example.”

The show, based on the memoir of Maria von Trapp, “The Story of the Trapp Family Singers,” is the tale of a woman who leaves a convent in Austria to serve as governess to a widowed naval officer’s seven unruly children. The 1965 film version, starring Julie Andrews and Christopher Plummer, won five Academy Awards, including Best Picture.

More than 50 Susquehanna University students are involved in the production, along with a dozen children who are triple-cast in the roles as the von Trapp children. The cast has been rehearsing since early September, and as opening night nears, rehearsals become more intensive.

“It’s pretty terrifying,” according to Melanie Harker, a junior from Edison, N.J., who plays Maria. “This is my first real role. Up to now, I’ve been climbing up. Now I get to use everything I’ve learned.”

Harker said she’s had minor parts in previous SU productions, and she’s looking forward to being in the spotlight.

“It’s scary to have the whole show resting on your shoulders,” she admitted. “This is it, the big cheese.”

Kelsey Zimmerman, of Lititz, said her role as Mother Abbess is an opportunity to try something different.

“I play a very old woman, and I had to learn to act old,” she explained. “I had to explore a different way of moving, a different way of holding myself.”

The actors had yet to work in costume, Powers explained, because most of the costumes were rented and would not arrive until a day or two before the opening night.

“I’m looking forward to trying out the nun’s habit,” said Zimmerman with a laugh. “I have to see if I can walk in it.”

Harker and Zimmerman both said working with the children, who range in age from 6-12, has been a lot of fun.

“They’re lots of fun,” said Harker. “They’re really good about learning their lines and they’re quite innovative.”

Zimmerman said their enthusiasm is infectious.