Um. I think its because its black and black conducts heat. DON'T TELL YOUR TEACHERS THIS IT'S JUST AN IDEA!
Please if you do tell them that its an idea and if you'r old enough to go to uni or collage you should be answering this, not me.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.