Crumpled sheets reveal a mechanism for glassy relaxations

We often crumple a scrap piece of paper into a ball before throwing it. This mundane action, however, creates a unique complex system with surprising mechanical properties. Take a thin plastic sheet such as cellophane and try it yourself. While a regular flat sheet will simply bend under the influence of gravity, a crumpled sheet is stiffer and can hold its own weight. It also has shape memory—it has many stable configurations and thus will tend to keep the shape it is deformed to.