American Eductional Products Fire Syringe: Demonstration of Combustion of Gas at High PressureDemonstration of Combustion of Gas at High Pressure For grade 7 9 and 12 15 ages An unobstructed view of the action inside the tube Designed to provide a safe but very dramatic demonstration of the generation of heat by gas under compression. The piston inside a heavy walled combustion tube is housed inside a transparent plastic outer cylinder which provides an unobstructed view of the action inside the tube. Cotton at the bottom of the tube ignites