Floating is Fab a Roone Tweenies : Season 4 Episode 16

It is Doodles' bath day and he is hiding from Max and will not go near the bath. The Tweenies discover which objects float and sink, and make boats race in the bath. Milo has a plan to get Doodles into the bath. He lays a trail of dog biscuits, but Doodles has a better idea.