A pneumatic air gun has a lever at the base of the gun, which controls a piston in a small tube. A check valve inside the tube allows air to flow into the tube but not back out again. By pumping the gun, more air enters the reservoir, which has a set volume. The more the gun is pumped, the more the air inside the reservoir is compressed. When the gun trigger is pressed, the compressed air pushes the bullet (or BB or paintball marker) forcefully out of the gun.
Is social media the result of our need to share?
Answered by John Perry Barlow
What happens if an inmate breaks a prison rule?
Answered by Discovery Channel
What subjects won't work for an X Prize competition?
Answered by Peter H. Diamandis