The practical implications of thermochromic compounds are numerous. Liquid crystals change geometry gradually depending on the temperature. Therefore, they can begin black and exhibit all colors of the spectrum depending on the temperature.(5) They have applications in thermometers for rooms, kitchen appliances, and even medical uses. Although liquid crystals change geometry slowly, they are still classified as discontinuous thermochromic compounds because at different stages of the geometry change, the observed colors are very different.