Sandi Toksvig reveals a very surprising table tennis fact in exclusive QI clip

Tonight, Sandi and Alan are joined by comedians Zoe Lyons (making her first appearance on the show), Tom Allen and Susan Calman to tackle more R-themed riddles and reasonings, including racket sports.

They even get to play with props (which always ends well, doesn't it?!), when Sandi gives them all a table tennis racket for a special experiment.

Sandi asks her guests to do a simple test: throwing the racket up in the air and trying to make it land on the same side. Shockingly none of them are able to do this and it turns out that there's a complicated scientific reason for this, which has nothing to do with heavy paint or gravity...

Check out this exclusive clip to see what we're banging on about, and then have a look to see if you've got a table tennis racket at the back of the shed, so that you can try it out yourself. If you manage to buck the trend, please don't tweet us.

This is the 18th series of the clever panel show, with bamboozling questions set by the QI Elves, and Alan Davies on hand so the rest of us don't feel quite so alone when we get the wrong answers.

Other guests still to appear this series include Joe Lycett, David Mitchell, Johnny Vegas, Josh Widdicombe, Liza Tarbuck and Sara Pascoe, who will discuss R-related topics including roundabouts, Rome and raspberries.

QI continues on BBC Two tonight at 9pm. To find out what else is on, check out our TV Guide.