Students in grade 2 learned about warm and cool colors and tints and shades. I saw a similar image on Artsonia a while back and tried to find it but could not so I have no idea who originated this lesson.
Students first drew an ear of corn with the husks at the top in black oil pastel. They filled in with each kernel using cool colored paint that was pre-mixed.
We used tints and shades of blue and purple for the corn. When the corn was finished, the students painted the background using warm colors.