They can flow like a liquid and bounce back like a solid. Masses of fire ants show a duality that intrigues physicists.

There is a lot of talk about how 3D printing could revolutionize the way that we make stuff. But what is 3D printing and how does 3D printing allow us to make almost anything from nothing? Professor Tim Minshall, Head of the Institute for Manufacturing at the University of Cambridge, explains it in this video, which is targeted at school-age students.