IN THE CLASSROOM:

For 40 thunderous minutes every week, music teacher Sarah Grenier teaches fourth graders at Eastbluff Elementary School musical notes with the aid of Boomwhackers, colorful hollow plastic tubes that emit As, Bs, Cs and Gs when hit against something.

Think PVC pipes whacking the ground and creating a melody.

Well, the melody comes much later in the class. After a few lucky kids pass out the Boomwhackers, color coded with notes printed on the outside, what you have is a room full of 9- and 10-year-olds with plastic tubes built for whacking.

It’s like being in Angel Stadium surrounded by Thunder Sticks.

Grenier quickly reins in the rumbling, and soon enough the kids are harmonizing.

“Gee, golly, gee, I. C-A-B-G,” Grenier sings. As she sings the notes, like an orchestra conductor, the kids with the appropriate sticks are cued to boomwhack the ground, emitting a tune.

The fourth graders start the class with light harmonizing. A lot of “do-re-me-fa-sol-la-ti-dos.”

Soon enough though, they move to the best part.

“It’s really weird that they make music with one kind of plastic,” says 9-year-old Briarly Beauchamp. “It’s fun.”

“They love anything they can hit,” Grenier says. “The Boomwhackers are such simple instruments. Any time I need a five-minute space filler I can pull these out.”

While Grenier sticks with conventional instruments such as tambourines, bells and wood for younger kids, she likes to experiment when it comes to fourth graders.

The Boomwhacker music industry isn’t limited to sticks. The sticks come with a book of suggested songs.

Grenier has been using Boomwhackers for two years and said one of their strengths is their ability to strike one note. The kids can learn the octaves one at a time.

Fourth grade teacher Karin Selby looked on recently as her kids pounded and whacked their way into a fervor, knowing the boomwhacking would soon come to an abrupt end.

“We’re having a test after and they’ll have to come down real quick,” she said, laughing.

Forty minutes after the fun began, the kids returned to class for their test — their fun crashing down with a boom and a whack.

JOSEPH SERNA may be reached at (714) 966-4619 or at joseph.serna@latimes.com.