HOW DOES THE HOOKAH PIPE WORK?
The vase of the hookah (usually a glass receptacle at the base) is filled with water up to the point where the stem (visible through the glass) is submerged. The bowl (where the smoking material is placed) must then be covered a metal mesh (or foil paper with holes poked in it in the absence of a wire screen). After the special hookah coals have been lit and are burning hot they are placed on the metal screen, heating up the smoking material to the point where it heats up and begins to smoke. At this point the hose is used to suck air through the pipe, helping the tobacco to burn and smoke properly.
The pipe works due to the fact that sucking on the hose pulls the smoke through the down stem into the vase holding the water, where it is filtered and cooled, the smoke then bubbles through the water and is pulled through the hose port opening. The hose is connected to this port and this is the last part of the smokes journey, where it passes through the hose and directly to the mouth of the smoker. Most hookahs feature a release valve which is used to clear out stagnant smoke from the hookah.
When drawing on the hose, the suction keeps the release valve shut to maintain the vacuum necessary for the pipe to work. If the smoker chooses to blow on the hose instead of sucking, this sends the smoke back into the vase, into the release valve port opening and up into the release valve. The air being blown back into the hookah forces a metal ball bearing (which is ordinarily shut tight while sucking on the pipe) to lift up, thus allowing the smoke inside the vase to be released.