What you need
What you do
Photocopy your graph paper onto the sheet of acetate and cut out a circle that fits the drain pipe aperture. Place the acetate circle into a plastic Petri dish and stick this on one end of the drain pipe. For accurate canopy cover measurements, there will need to be around 100 squares of graph paper visible through the drain pipe aperture, but in reality this may not be possible so students will have to estimate the percentage coverage.
When you use it
These pieces of equipment can be used to estimate percentage canopy cover at different sites, and are useful alternatives to expensive light meters. Use them during ecosystem studies to investigate the amount of light that reaches the forest floor in dense woodland and clearances. Alternatively, use them in rivers or on rock surfaces to record sediment particles size in situ.