I nvite a respiratory therapist to speak to the group about how the lungs function and the symptoms of respiratory disease. The flame will quit burning within a few inches, well above the visible layer of gas. If you allow a few minutes for the gases to accumulate the flame will burn out just beneath the slatted floor. S earch the internet for manure pit web sites. A good place to start might be the University of Minnesota's manure education and research page .
M ake a slatted top for the manure pit.
Cut two pieces of screen trim the length of the pit . Cut thirteen pieces of screen trim the width of the pit. Glue the short pieces onto the long pieces being careful to space them evenly apart from each other. Make one of the center spaces wide to make it easier to put a match between the slats. Paint the slatted floor grey.