The band's three members, who all study at King George V School, in Kowloon, joined last year's Music For A Cause competition held by local charity Kids4Kids.
Their song, Living In A Fire, was selected to start off the charity's album, The World Around Us, which has been on sale since March.
"We're all trying to fight different 'fires'," they say of the song's title. "Every single one of us in Hong Kong and [elsewhere] is trying to fight fires."
Edwina Lau, Jessica Chu and Jason Lee, all 16, wrote the song together. "A fire is something you can't escape, like poverty and other Hong Kong social problems - like you're trapped in it," Jason says.
Jessica says: "Our lyrics reflect what's going on in Hong Kong; like the huge wealth gap between the rich and poor."
Edwina says: "People here are all just too busy to notice the problems that are going on around them."
The trio first met at their GCSE music class two years ago and felt a special connection. They launched a band for the Kids4Kids music competition in July last year.
Jessica says: "We were already composing and performing together before. But the competition gave us a reason to become more serious about our talents and passion."
Jason says of their name, Scr@ch: "It's sort of like a DJ scratching the disc, you know? It represents our kind of music, which is mostly pop-influenced."
All three have distinct roles, based on their individual talents. "Since Jessica and I are good with lyrics, we do the writing," Edwina says. "We complement one another; Jason is much better at the technical stuff and the mashing up of songs."
The group credit their winning piece to the influence of the US hip-hop group The Black Eyed Peas and their 2003 hit Where Is The Love?.
The students say they want to engage their audience by singing about social issues such as drug abuse, racism, the wealth gap, and inequality.
"We tried to make the song
more global by dealing with pressing social issues. We want listeners to think about questions like, 'Where's the love? Where's the hope?'," Edwina says.
The band's members subscribe to Kids4Kids' idea that teenagers can make a difference in the world, too.
"Kids4Kids takes a meaningful approach in offering opportunities
to teenagers to learn about the issues and be more caring," she says.
"With our music we want to help, too. It's better than just asking people to donate [money] in a box."
All proceeds from The World Around Us, on sale at Kids4Kids, Bookazine, Pollux Books, Toy Club go to charity. For details go to Kids4Kids