Blind see colors by touch?

Here is a simple experiment. I did this many times as a kid with a near 100% success rate.

Get a Nerf brand football (american football) that has one side black and the other side any other color. (Mine was black and bright orange. I'm sure they still sell them.) Keep the football away from any intense lightsource such as sunlight coming in through a window. This will make ensure that it has a uniform temperature and one side is not over-heated. Close your eyes and hold the football in your hand turning it over and over until you have no idea which is the black side. Keeping your eyes closed turn the ball more slowly and feel the temperature of the ball with your finger tips. After some practice you can sense a very slight difference in temperature between the two colors. The warmer side is the black side. I could guess it nearly every time. I guess I was pretty board in those days. Try it before you knock it.

Danny