Don Herbert, who explained the wonderful world of science to millions of young baby boomers on television in the 1950s and '60s as "Mr. Wizard" and did the same for another generation of youngsters on the Nickelodeon cable TV channel in the 1980s, died Tuesday. He was 89.

"Over the years, Don has been personally responsible for more people going into the sciences than any other single person in this country," George Tressel, a National Science Foundation official, said in 1989.

"I fully realize the number is virtually endless when I talk to scientists," he said. "They all say that Mr. Wizard taught them to think."

RIP Mr. Wizard.