Hey Vat19 fan! 

The trick behind the cool Vat19 stuff that changes color when heated or cooled is called “thermochromism”. It’s the same basic technology behind mood rings: when heated it changes color and a new design comes out. When cooled it returns to the original state!

Other companies have used it to let parents know when milk has cooled enough to feed babies or even when a kettle has boiled. We have selected some awesome products that will put a smile on your face. Enjoy a new creative dimension with your puzzles and putty!