This amazing plastic sheet remains black except for a 10-degree temperature range. 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. Build the Heat Sheet Panel into a play house and explore thermal conduction just like the pros! Comes with adhesive backing, for easy installation in the frame side of a Panelcraft panel, and activity guide. Panelcraft panel sold separately.