The Johnny Ball photo clippage challenge

He's the man of a thousand faces, every one a different version of open-mouthed, wide-eyed exuber-ism. But what particular historical epihanies are being depicted by those thousand faces in each of the following?

1) "Fear not - *oil* soon get it working again!"

















2) "Those who said the world was round used to get carted off. Hence the name: cart-off-graphy!"























3) "Pardon me if I sound a little burnt out; things have been getting on my wick!"























4) "I used to do this for a living, but my business plan went totally to pot!"