Making a Liquid Crystal Thermometer

This lab, presented by the National Nanotechnology Infrastructure Network, introduces students to the temperature response of liquid crystals, and how they respond in different phases of matter. In addition to liquid, solid, and gas, the fourth phase of matter includes liquid crystals which "have the particles arranged in a helix, and the color reflected from the liquid crystal depends on the pitch of tightness of the helix. The pitch, which changes with temperature, equals the wavelength of the light reflected which creates the color of the liquid." This can be found in nature, and is also in digital displays. In this lab, students will examine the changes in liquid crystal color and behavior when heat is applied. Included in this lab are a teacher preparation guide, student guide, and a student guide with answers.