Organizing 40 teenage girls is not usually made easier by loud rock music.

But on a recent afternoon at Billings Middle School in Green Lake, Dani Chang, director of Rain City Rock Camp for Girls (RCRC), makes it work in her favor. Standing onstage in a yellow T-shirt graffitied with Sharpie, she is prepping rock campers to rehearse for their showcase the next day.

“You are the audience as well, so act how you want others to act when you are onstage,” she says.

A few times, a girl misses a beat or hits the wrong chord or forgets a lyric. At rock camp, apologizing for mistakes is not allowed. Girls can only say, “I rock,” and keep playing. Each time a girl forgets the rule and starts to apologize, the girls in the audience sincerely yell that she rocks.

This is important because, as operations manager Michelle O’Connor points out, Rain City is not a music proficiency camp.

“They are just learning crunchy chords,” she says. “It is about them being so proud of themselves, and that is all that matters.”

Founded in 2009 under the name “Girls Rock! Seattle,” RCRC, a nonprofit organization, is part of the Girls Rock Camp Alliance, which sprouted from Portland’s Rock ’n’ Roll Camp for Girls, founded in 2000.

About 70 girls ages 8-17 — and just as many volunteers — gather for each weeklong session of RCRC summer camp, which was offered twice this summer. Many of the campers have never touched an instrument before, while others have taken lessons for years. Each girl’s skill level is not what’s important. What is important is that they learn to take chances, work together and express themselves creatively through music. (RCRC also includes daily workshops which teach girls about themes such as social justice, empowerment and leadership.)

Participants are assigned to groups based on friend requests, age and instrument preference. They name their own bands and write their own songs.

Campers eventually perform their songs at a showcase, the Saturday after the last day of camp. In addition, this year there is Thursday’s Rain City Rock Camp for Girls Showcase at The Neptune Theatre, featuring bands from both summer camp sessions, RCRC’s Ladies Rock Camp and RCRC volunteer bands. It’s free, part of Seattle Theatre Group’s Nights at the Neptune series, a program launched in June to give voice to emerging projects in exploration of issues including social justice.

As the rehearsal continues, Ella Hansen, 17, scurries back and forth replacing guitars, adjusting sound and whatever else she can do to help things run smoothly. Once a camper, this is Hansen’s third year as an RCRC intern.

For her, watching girls go from timid on day one to screaming at the showcase is cool to experience first as a camper and now as an intern.

“It’s just seeing them love themselves and know that being energetic and loud is OK,” Hansen says. “It’s not just that girls can rock, too — they can actually rock.”

Hannah Leone: 206-464-2299 or hleone@seattletimes.com.