Creating a 3D model of a landscape using play doh then mapping the contour lines onto graph paper
Play doh - http://www.instructables.com/id/How-to-Make-Playdough-Play-doh/
Graph paper - I print my own onto A4 sheets of paper
Optional laminated graph paper
Provide one lump of play doh per patrol and ask them to create their own mountain range on the laminated sheet of graph paper.
Each scout is then challenged to draw the contour lines of the mountain range onto their own sheet of paper