So it's a good thing for Cary entrepreneur, educator, author and TV personality Marshall Brain that his edutainment franchise continues to grow. His new TV series "Who Knew? With Marshall Brain" debuts at 9 p.m. Thursday on National Geographic Channel.

The one-hour show, which gives viewers a close look at the world of product design, manufacturing and testing, is another step on Brain's road to name recognition as being one of the nation's go-to smart guys.

"One of the things that we do in the show is that we explain the design and engineering and the actual mechanics of how you create, for example, a carbon fiber bicycle, or a handgun, or a fire extinguisher," he says.

Or maybe something yummy he can bring home to his kids (Brain and his wife, Leigh, have four children). He spoke Friday, while he was on his way home from San Francisco after shooting a segment at the Guittard Chocolate Co. factory.

"They do make bars of chocolate like you would buy at a candy store, or something," he says. "But they mostly make bulk chocolate that other companies then use to make their chocolate. If your company doesn't want to actually import the beans, and roast the beans, and do all that part of the process, then you'd buy the chocolate in these giant 10-pound bars, or by the tanker truckload from Guittard."

Each "Who Knew?" show features three segments, and the Guittard Chocolate profile will appear in one of 10 episodes to air this summer. Three initial episodes air in March, and in Thursday's premiere, Brain visits the Sea Ray boat factory in Vonore, Tenn.; Zambelli Fireworks Internationale just outside of New Castle, Pa.; and the Titleist golf ball facility in Acushnet, Mass.

Brain, who is self-deprecating about his own golf skills, was particularly impressed by something he learned about products available for the discerning golfer.

"There's actually 2,000 different kinds of golf balls," he marvels, laughing.

Brain, 46, taught computer science at N.C. State University for six years. His How Stuff Works Web site (howstuffworks.com) evolved from a hobby to a phenomenon soon after he started it in 1998. He went on to write popular science articles and a few brainy books as well including "Manna" and "The Teenager's Guide to the Real World."

It wasn't long before television wanted him, and he began racking up appearances on shows including National Geographic Channel's "Everyday Things" and Fox News' "Fox & Friends."

But there was one January 2006 TV appearance that really changed his life, which he mentions when asked about how his new show came about.

"I'm not completely sure," he says, laughing. "But I can tell you, this is a long, side-effect chain from getting to appear on 'Oprah.' It definitely had kind of a seismic effect on my life. And this show is part of that side-effect chain. It's surprising and amazing to me."

Among his next few projects, Brain says he's in the proposal stage for another book, and he keeps plugging away at How Stuff Works.

"I'm currently doing an article about the Large Hadron Collider about to power up in Europe," he says. "This is sort of the norm for me."

And he says that although "Who Knew?" is aimed at adults, he can see that it could have the effect of triggering the entrepreneurial spirit in some of America's young people.

After all, as he points out: "Companies are started by people -- normal people."

Repeat visitor

Raleigh Realtor Sharyn Fuller, who was featured last year in the premiere episode of HGTV's "Buy Me," makes a return appearance on Monday.

In the episode, Fuller, who works for Fonville Morisey Realty, helps a single mother restore and sell a home that has fallen into disrepair in the more than 11 years since her ex-husband moved out. The episode was filmed in June 2007.

Fuller's episode of "Buy Me" airs at 10:30 p.m. March 17.