Liquid Crystals Movies

Liquid Crystals Video No. 1 - Examine the flow of nematic liquid crystals under polarized illumination at a magnification of 200x with a playing time of 9.9 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (4.26 MB).

Liquid crystals are sometimes referred to as the "fourth state" of matter following gases, liquids, and solids. The individual molecules flow past each other as they do in a liquid but tend to be oriented in the same manner, like the molecular arrangement in a solid crystal. However, the molecular forces maintaining the liquid crystal state are sufficiently weak that it can be maintained only over a limited range of temperatures and pressures. If the liquid crystal substance becomes too cold, it reverts to an ordinary solid. If it becomes too hot, it reverts to an ordinary liquid. It is also easily affected by changes in mechanical stress, electromagnetic fields, and chemical environment. Although it displays characteristics of both a crystal and a liquid, the liquid crystal state also has properties that are unique.