Agatha Christie's plots, if you look at them you'll find they're mathematical too. She's not, of course. But such tricks and laws underpin everything we do. With technology expanding that's the biggest opening for kids. When he first started presenting he was explaining what calculators do, but now half his audience have mobile phones.
Computers can abstract things too much.
Once we stop talking to each other we forget that we're human. Like that old Italian stereotype Fibonnacci - he's Italian, so Johnny portrays him singing Just One Cornetto. Johnny can't really be serious about science. He likes making them squirm. Indeed, his favourite anecdotes are the in-jokes, of holding his breath while a cyanide loaf that could have killed someone bakes in the oven on Reveals All , on studio lights melting the plastic costume he was wearing onto his neck.