What are CAT Stickers?
CAT Stickers are stickers coated with a mixture of cold activated thermochromic dye and paint pigment.
CAT Stickers can be purchased here: CAT Stickers.
The CAT stickers shown are yellow at room temperature and when cooled to 150C (590F) the stickers change from yellow to a red-orange color. Cold activated thermochromic dyes are transparent at room temperature this is because the shape of the thermochromic dye molecules allow white light to pass through. (White light contains all the colors of visible light). The CAT mixture shown in the diagrams is yellow at room temperature because of the yellow paint pigment in the mixture.
At its activation temperature, which is 150C (590F), the shape of the molecules of the thermochromic dye reflect red light. The CAT mixture is a combination of red thermochromic dye and yellow paint pigment. When viewed under white light (sunlight or indoor lighting), the thermochromic dye molecules absorb all of the white light except red, thus it reflects red light to your eye. The yellow paint pigment reflects yellow light to your eye. When different colored light waves are close together when they enter your eye, your brain perceives them as one blended color. The red and yellow light waves are perceived as a reddish- orange color.
When the cooled CAT Sticker warms to room temperature its color reverts back to yellow. This is because the CAT dye is reversible, meaning it molecular structure changes back and forth in response to changes in temperature.
CAT STICKERS: FUN for ALL
Even toddlers can have fun with CAT stickers. Marking on CAT stickers with a piece of ice causes the stickers to change colors. When the sticker warms it reverses back to its original color.
For more fun with CAT Stickers see
There are three different CAT Sticker Colors and they all have the same activation temperature, thus they can easily be cooled using ice.
CAT stickers are coated with a mixture of two different colorants (materials that give color to what ever it coats). The two types of colorants used are paint pigment and cold activated thermochromic dye.
Study the colors of the three samples of CAT stickers and identify the possible colors of each colorant combined to produce the CAT Mixture.
Clue: For each CAT sticker, colored light is reflected from the dye molecules as well as from the molecules of paint pigment.
Clue: Remember that when different colored light waves are close together when they enter your eye, your brain perceives them as one blended color.