We just learned about the Ball Valve.
Another type of valve is the Poppet Valve.
This is a valve that is usually used to open and close for gas to come through.
In a car's engine there are valves used to help the fuel come in, and after it makes a big explosion there are valves to let the burnt up air out.
![poppet valve](https://upload.wikimedia.org/wikipedia/commons/0/05/Poppet_valve_red.jpg)
![poppet valve](https://upload.wikimedia.org/wikipedia/commons/d/dc/4StrokeEngine_Ortho_3D_Small.gif)
(from: wikipedia - poppet valve)
Kid Facts - Blast from the past: Bell X-1