Place a warm object on it, like your hand, and the color changes from black to red, red to green, green to blue, and finally back to black again! The Heat Sheet empowers children to explore concepts of heat and light energy in their surroundings. Comes with adhesive backing, for easy installation in the frame side of a Panelcraft panel. Panelcraft panel sold separately. Compatible with solid panels. Set of 5. Grades PreK+.