Observational drawing is one of my favourite ways to 'teach' drawing to my Grad 4,5 and 6 students.
It forces the kids to really slow down, look at the small details
and 'draw what they see, not what they think they see'.
For this lesson, I just grabbed a variety of leaves from a park near my school. The kids chose which leaves they liked and placed them on a sheet of white paper. This allows them to see the cast shadows easier. I turn off all the lights in my room and just use the natural light from my windows.
I show them how to do a contour drawing of line first, then once all the proportions are correct, to slowly start adding shading.
This student tried to add water droplets to her leaves for a more naturalistic look.
The week before we did drawings of Werther's Original candies!