Our World in Art: Light.

"A glimmer of light cannot truly be seen without much that is dark, and darkness cannot truly be felt without shadowy forms rising from the blackness." Anonymous

"Ideas are to literature what light is to painting." Paul Bourget

"Daylight is too easy. What I want is difficult: the atmosphere of lamps or moonlight." Edgar Degas 

What I would add here and now is: Second graders, congratulations on your achievements! :-)