This is made of the same substance as mood rings. From the text on back of the sheet: "The liquid crystals on this sheet exhibit brilliant changes in color when exposed to slight differences in temperature between 77 F and 90 F. Called cholesteric liquid crystals...they exhibit both the flow properties of a liquid and the optical properties of a crystal in that they scatter light selectively."
This is made of the same substance as mood rings. From the text on back of the sheet: "The liquid crystals on this sheet exhibit brilliant changes in color when exposed to slight differences in temperature between 77 F and 90 F. Called cholesteric liquid crystals...they exhibit both the flow properties of a liquid and the optical properties of a crystal in that they scatter light selectively."