9 and 10 year olds.
This is a very enjoyable lesson with striking results. I have taken this with younger children water pipes with water colour paint.
This time the children tried to address the issue of light coming in from one direction. Therefore they had to blend their oil pastels. They also tried to include taps, junction boxes, and thinner pipes in the background.
A Fab Follower has suggested a book to read before this lesson...The Lost Thing by Shaun Tan.