I grew up with his shows, a regular Mr. Physics . . .
He was a joy to listen to, to see him in action. He would work a number of complex experiments, but all of them easy for any kid to understand. He was quick, too. If the experiment did not work as he had described, perhaps for a failing in the material he was using, his comment would "Trust me!" and then on to the next experiment.
He had a short period of reruns, I think on PBS in the 90s, but was a spokesman for Cadbury chocolates commercials in the 70s or 80s.
Put simply, he was quite impressive.