How Do Mood Pencils and Mood Cups Work?

How do mood pencils work? Color-changing items have been around Since the 1970s when the first mood rings began sweeping the nation. Since then, color changing techniques have been developed for use in all sorts of fun products. Mood items like pencils are thermochromic which is a fancy way of saying they change color, with changes in temperature. This color change effect Is manufactured in one of two ways. The first are pigments that contained thermo chromatic liquid crystals or TLC’s TLC’s are fluid like a liquid, but their molecules are very structured and organized, similar to the properties of solid crystals to make pigment. TLC’s are micro encapsulated, keep the crystals from being damaged. Then the capsules are floated in a chemical base When the TLC’s are exposed to warmer temperatures, they recognize and reposition themselves and thus reflect light differently We can’t see this happening but what we do see is a color change TLC’s are very temperature sensitive, which makes them perfect for medical thermometers, aquariums, and refrigerators. Color, change can also be achieved through the use of leuco dyes. Leuco dyes are tiny capsules filled with three substances: a colorant, an acid, and a solvent. At low temperatures the solvent is solid. The three types of particles hang close together and reflect light. As the temperature rises. the solvent liquifies, letting the particles float freely. The leuco dye becomes translucent allowing the color of the material underneath to show through. Leuco dyes work at a much wider temperature range with more color options than TLC’s so they’re great for novelty items bath toys, mood cups, and trusty mood pencils. And there you have it – mood pencils and the secrets to color changing products. A little science, a little artistry, and a whole lotta fun!


  • oxAuthor Alicexo

    What if you're just hot?

  • Angela Treannie

    I am a high school chemistry teacher, and this video was perfect! Thank you!


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