When I did the actual lesson in class, I had this assortment of squash and gourds for kids to see and touch. I also had this photo displayed on the Smartboard so that everyone had a good view.
I asked them to imagine any of these outside on the ground after a rainstorm, when the sun came out. What would they see? -- A reflection, of course.
Students drew their pumpkins, etc. on a fold line in the center of their paper (just regular copier paper) using Crayola watercolor markers (Classic set). I emphasized shading and leaving white highlights where the light hit the top of each squash. Then they brushed water on the bottom of the paper, folded the dry half onto the wet half, pressed thoroughly and VOILA!! Reflections everywhere!!
As you can see, we talked about overlapping, shadows and blending colors. I also mentioned that their final results would look different once they added the water and that it was a bit of an experiment in that sense.