I made slime with this. The slime recipe wasn't great, but the pigment worked! I also added it to some paints and it worked with paint too! Fun product to try.Most of the thermochromic powder (color changing with heat) I've gotten has been very similar, for all I know it all comes from the same factory.This is *31C (~88F)* color changing, meaning it will be black most of the time, but change to white (or clear, in liquid) under heat (body heat, hair dryer, etc). This is good for covering secret messages that reveal with heat.Applying the powder is a bit tricky. You have to mix it with some kind of clear binder base. You can get acrylic base, or just use clear-dry (Elmer's) glue of some kind. The powder doesn't "want" to mix, you're going to have to spend a minute beating each batch into the base. You'll need to experiment with the right ratio, but start with something like 1:8 (powder to base, by volume) and adjust to minimize powder consumption while still applying in an opaque coat.It's also available in other temperature-thresholds (instead of 31C) and colors (instead of black-to-clear). While this worked OK, for use on paper I found it inferior to a proper thermochromic *ink* as made by Atlanta Chemical. Your mileage may vary!I purchased this black thermochromic pigment for use in nail acrylic. The "mood changing" polishes don't tend to work well over acrylic (for me, anyway), so I decided to try a more direct contact approach. I mixed it 1:1 with a clear polymer and had good results. The color was quite opaque. It set up just as it should. It's cool to watch it work as the chemical reaction occurs and settles. I did purchase the lowest temperature version to ensure an effective result. Throughout the day, I do notice it changing as the temperature of my hands changes. Even at the warmest, this particular 77°F thermochromic pigment (black to white) did not go full white, but more of a light-medium gray. I did a test piece that I sealed and submerged in near boiling water, and again, it did not lighten beyond a light-medium gray. I'm not in any way dissatisfied with that, but it should be noted if that's what you are after.My particular application is quite small and underwhelming, but fun nonetheless. I think doing a tabletop or countertop, or even acrylic handles, say for custom knives, would be incredibly awesome! You'd know if someone was just touching your stuff or if the cat was just on the counter. ;)If you're on the fence, buy it. It's worth it for some fun!bought this for making some kids color changing shoes its not nearly as red as i would like but works wellI bought the red thermochromatic pigment to make color-changing slime. The pigment provided dramatic, reliable color changes at reasonable temperatures. I used a slime recipe I found on a website called "Left Brain Craft Brain" which worked very well (this was a school glue + liquid starch formula. See their website for the full recipe). The recipe had me add food coloring to provide a "contrast color" for when the slime is warm -- I chose yellow food coloring for this.At room temperature (64 F), the slime is a bright orangey-red. When placed against a jar of hot water, the portions in contact with the warm glass turned pale yellow (without food coloring, the warm portions would have turned white instead). When placed against an ice pack, the parts touching the ice turned a more saturated orangey-red. The color changes were very striking and satisfying, especially the "room temperature to hot" transformation.Highly recommended for homemade slime.I ordered the red thermochromic pigment for my daughter's science fair project. She used the pigment to add to one of her slime recipes and it worked perfectly. When warm, it turns a light pink and when cold, it turns a dark pink/red. We used ice to write our names in the slime, then we put the slime in the freezer and used our fingers to warm it back up making fingerprints on the surface. I highly recommend this pigment to anyone looking to do anything similar.It worked to make color changing slime. I think they should have gave more considering the price.