Some children's television hosts are sweet and lovable, like Mr. Rogers. Not Mr. Wizard, apparently.

Don Herbert, host of Nickelodeon's science program "Mr. Wizard's World" from 1983 to 1990, may have had a knack for educating young minds, but as this video points out, his tutelage could be austere and rather cruel.

In this supercut from "Mr. Wizard's World," Herbert repeatedly berates and chides his young students, who were child actors that appeared on the show, ostensibly to learn something from the experiments that he conducted.

It wasn't Herbert's only foray into television. His first show, "Watch Mr. Wizard" ran on NBC from 1951 to 1965, and was later revived on Canadian television. Before that, he served as a WWII bomber pilot, flying missions over Germany and northern Italy. Perhaps that's where he got his hard edge.

Yet, stern as he could be, Herbert was loved and respected.

"Herbert's techniques and performances helped create the United States' first generation of homegrown rocket scientists just in time to respond to Sputnik. He sent us to the moon. He changed the world," Bill Nye, another prominent TV science teacher, wrote in Herbert's 2007 Los Angeles Times obituary.