"To explain rain, he boils water in a coffee pot, compares the steam to clouds, and shows how 'rain' will condense on the sides of a glass held over the spout."
In "Saturday Morning TV," a 1981 book by Gary H. Grossman, Herbert recalled pouring two colorless solutions into one glass and then announced that the solution would turn black before he counted to nine.
"I got up to 20 and decided I'd better stop," he recalled. "I explained that apparently other factors like temperature and acidity had interfered with the experiment."
But as he finished his explanation, the liquid changed color.
"It was embarrassing, certainly, but I discovered the answer," he said. "We hadn't used a fresh solution, so the reaction was slower than expected."
After "Watch Mr. Wizard" ended its 14-year-run in 1965, Herbert showed up frequently on talk shows, including "The Tonight Show" and "Late Night With David Letterman."
"Watch Mr. Wizard" was revived in 1971 for a season, and "Mr. Wizard's World" ran on Nickelodeon from 1983 to 1990.
Born July 10, 1917, in Waconia, Minn., Herbert later moved to Minneapolis and then La Crosse, Wis. He graduated from LaCrosse State Teachers College in 1940 and could have taught English or general science — his majors — but he recalled later that he was more interested in the theater.
He worked as an actor and stagehand in a Minnesota theater group before moving to New York City in 1941.
A year later, he volunteered for the Army Air Forces. As a B-24 bomber pilot, he flew 56 missions over Italy, Germany and Yugoslavia and received the Distinguished Flying Cross and the Air Medal with three oak-leaf clusters.
Herbert wrote several books, including "Mr. Wizard's Supermarket Science" and "Mr. Wizard's Experiments for Young Scientists."
In recent years, he helped set up his website, http://www.mrwizardstudios.com .
He is survived by his wife of 34 years, Norma; his two sons and a daughter from his first marriage, Jay and Jeffrey and Jill Rogers; his stepdaughters Kendra Jeffcoat and Kris Nikosey; his stepson, Kim Kasell; and 13 grandchildren.
The family plans to hold a private memorial service.