In this activity, learners explore liquid crystals, light and temperature. Using a postcard made of temperature-sensitive liquid crystal material, learners monitor temperature changes. By observing these changes, learners show that dark materials absorb and reemit the energy contained in light more readily than light-colored materials. Learners can also distinguish energy absorbed and reemited by radiation, convection, and conduction by comparing the behavior of black, white, and silver objects. This resource guide includes detailed explanation of the phenomenon and background information about liquid crystals.