We just learned about the Intake Valve.
Another part of a car's engine is the Exhaust Valve.
Just like we learned that the intake valves bring fuel into the piston, after the fuel is used up it needs to be pushed out of the piston.
The exit, or exhaust valve opens up and lets all the burned up fuel out so the piston can start over again.
(from: wikipedia - valvetrain)
Kid Facts - Blast from the past: Hydraulic Brake
