Mike,
I gathered leaves for my students and explained that they were to draw
the features of their own leaf so carefully that I'd be able to match up
the leaves with the sketches later. It was very quiet in my classroom.
Quiet, rather slow music was playing on my CD player. If a student
was randomly drawing veins, I'd point out carefully how the veins
actually travel through the leaf. The final sketches were wonderful -
and the students were invited to view each other's sketches afterwards.
This was with 2nd - 5th grade.