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.
(from: wikipedia - poppet valve)
Kid Facts - Blast from the past: Bell X-1
