Yeah, but why does wood float? There are two forces acting on the life jacket - its weight and the force of the water pushing upwards on it - the upthrust. And if the weight is equal to or less than ...

Deploy this example to create a 3D object reconstruction workflow that transforms stereo video input into high-quality 3D assets using state-of-the-art computer vision and neural rendering techniques.

See all the objects from the Radio 4 series A History of the World in 100 Objects. Click on any link to find out more about an object, zoom in on the image and listen again or download the programme.