It was an engaging and intriguing few hours where the students got to think through some of the issues that Jim and Sam need to consider as engineers. This included making predictions about mass, volume, displacement, shape, buoyancy and the centre of gravity before putting a wonderful assortment of things into the water tanks that Jim and Sam had brought with them.
Interesting and inspirational, I am sure that more than a few of the students now have engineering in mind for the future, but as Sam said, if you like tackling problems, working out how things work and how things are put together, working with people from all over the world and global travel; then maybe engineering will choose you!
PS. The rubber duck did of course float but would not stay upright because of the uneven weighting of the design. A headless rubber duck would be a more effective design, but not as much fun in the bath!