Ellie Simmonds v Ollie Hynd - who will Sink or Swim?

Paralympic gold medal winning swimmers, Ellie Simmonds and Ollie Hynd are two fierce competitors - but just how fierce are they?

When they popped into Newsround HQ recently, we set them a special challenge to find out who will sink and who will swim.

Check out the video to see who emerged as the winner.