In the background material to his Nobel Prize talk in 2010, Prof. Geim illustrated the strength of graphene with his now famous cat hammock example : The unit hexagonal cell of graphene contains two carbon atoms and has an area of 0.052 nm2. That translates into a density of 0.77 mg/m2. A hypothetical hammock measuring one square meter made from graphene would thus weigh 0.77 mg.

Scientists from the University of Nottingham and Loughborough University used a measurement method called picosecond ultrasonics, similar to medical ultrasound, …