LONDON (Reuters) - In a central London pub, a young bearded physicist is demonstrating how to build a model of the universe from plastic Lego bricks. Clue: you need a lot of them.
Across town, in different bars, other experts are probing the mysteries of cancer and dementia, life on other planets, and how to win a Nobel prize.
It's all part of the May 18-20 "Pint of Science" festival, a fast-growing event that gives scientists a platform in dozens of drinking establishments across nine countries to explain their research to the public.
The idea of talking science in a pub was dreamt up (in a pub) by two neuroscience researchers at Imperial College London. The festival has snowballed since it first got off the ground in 2013 and this year there are more than 600 science evenings.
After initially taking in a few pubs in London, Oxford and Cambridge, the 2015 line-up ranges across bars in 50 cities worldwide, including New York, Paris, Berlin and Sydney.
Co-founder Michael Motskin describes it as "TED talks with beer" - and the social drinking element is integral to success, he believes.
"There's a massive gap between what people know about science and what we actually do in labs," he said. "The best way to talk about it is not in a lecture hall but in a relaxed environment, where you can have a drink."
Most events in London, the hub of the festival, have been sold out for weeks as people have rushed for 3 pounds ($4.65)tickets to talks on everything from big data to what the nematode worm can tell us about the human body.
The hottest tickets, however, are for sessions on neuroscience and particle physics, which is where the Lego demonstration comes in.
Discussing science in the pub has a history in Britain, with James Watson and Francis Crick first announcing their discovery of the double helix structure of DNA in the Eagle pub in Cambridge in 1953.
Editing by Dominic Evans