Two students have used a 3D printer to put an end to one of mankind’s biggest frustrations – the puddle of insipid water that trickles out of ketchup bottles. The technical term for the process that leads to the separation of tomato paste and water is called syneresis, which can catch diners by surprise if they do not shake the bottle first. Two high school students in Missouri say they have invented the solution – a mushroom-shaped cap that holds back the unwanted water. Jonathan Thompson and Tyler Richards told a local TV channel the invention came about as part of a class project. "Our teacher wasn't even going to let us do this idea," said Jonathan. But after carrying out surveys and research, the teacher gave the pair the go-ahead. They are now hoping to get a provisional patent for the invention, before pitching it to ketchup companies.