Glass

An understanding of glass could lead to better products and offer headway in other scientific problems, yet scientists are still in violent disagreement about the nature of this gooiest of liquids and most disordered of solids.

The arrangement of atoms and molecules in glass is indistinguishable from that of a liquid. But how can a liquid be as strikingly hard as glass?

From the New York Times → The Nature of Glass Remains Anything but Clear