‘Impossible’ material would stretch when compressed
Imagine cushions that lift up instead of sinking when you sit on them. Impossible? Not according to a blueprint for new materials with “negative compressibility”: the materials compress when they are pulled and expand when they are pushed.
Zachary Nicolaou and Adilson Motter of Northwestern University in Evanston, Illinois, have now [theoretically] designed a metamaterial that stretches when compressed, and vice versa, under any circumstances.