Description: Item Name: Air Compression Ignition Tester Main Principle - a simple demonstrator of gas compression. When the gas is compressed quickly, the temperature increases. The tinder which put in the vessel will burn Put a small piece of cotton (size of a small bean) on the bottom of the piston. Then push the piston into the vessel very quickly. The cotton will burn with smoke. Other tinder materials with similar or lower autoingnition temperature may also be used. No tinder material is included. Great Educational Toy - It's suitable for junior high school physics course experiment teaching, cultivate children'sinterest in physics, more intuitive and easy to understand Note: Before the experiments, exhaust gas in the cylinder should be removed first. And some petroleum jelly can be used for the lubricating between the piston and vessel. Specification: Material: Metal and Plastic Color: As picture shown(color random) Assembled Size(DxH): Approx. 6 x 15 cm / 2.36 x 5.91 inch Package Includes: 1 Set Air Compression Ignition Tester