Liquid crystals, a state of matter which sounds as bizarre as hot ice cubes, are emerging as an important group of materials for NDT techniques. in fact, liquid crystals are performing so many NDT jobs that it is hard to keep up with new applications. Numbered among their advantages is the fact that they can detect a change in temperature in less than one-fifth of a second and can resolve flaws measuring less than one-thousandth of an inch. Currently, the crystals are used to detect voids, porosity, cracks and lack of bonding in metals and nonmetals.