Don't forget to use some imagination. I use it with all of my students and it is adaptable to any developmental level. The lesson easily integrates with math and science curriculum as well as covering many art specific objectives. Identify the positive and negative parts of the stencil. K-1 do geometric and free form shapes.
Upper grades can handle more complex shapes.
Arrange stencils on the drawing paper in a way that looks good to you. Scrub the brush onto the paint cake. Hold the brush bristles down towards the stencil and, using an index finger, pull back on the bristles allowing the bristles to flip forward thus spattering paint onto the paper around the stencil shape. If necessary replace stencil and spatter again. Overlapping enhances a 3-D effect.