How can you write an essay about how the color black attracts sun heat?

Sure! If you want to. It's your choice!

First, you have to start with a correct statement: sunlight isn't "attracted" to ANY color (e.g. like iron is attracted to a magnet). Instead, dark colors absorb energy better than lighter colors, so assuming the same amount of light falls on two different-colored objects the darker one will become warmer.