The thermal imaging card

The thermal imaging card 
Simply fascinating: 
Where this simple black foil gets warmer than 28 ° C, it starts to color red, and then goes through orange, yellow, green and blue to purple to turn black again above 34 ° C. During the cooling process, the process proceeds in the reverse order. This thermochromic characteristic makes impressive experiments, almost adjacent to sorcery, possible: when placed on a hand, it appears after a short time as a colored ghostly appearance. For example, if you place the heated foil on a coin, the fast color tone shows the heat-absorbing property of metal. 
Let your experimenting fantasy run free! 
Dimensions 105 x 148 mm, with micro-LCD layer encapsulated. Note: the manual is in German. Per Unit.