@DrMansoor:
Structure and operation
Components
The bowl
Also known as the head of the hookah, the bowl is a container, usually made out of clay or marble, that holds the tobacco and coal during the smoking session. It is covered in a small piece of tin foil and holes are made before the coal is placed on top.
Hose
The hose is a slender tube that allows the smoke to be drawn. The end is typically fitted with a metal or wooden mouthpiece.
Body, Gasket, Valve
The body of the hookah is a hollow tube with a gasket at its bottom. The gasket itself has at least one opening for the hose. The gasket seals the connection of the body of the hookah with the water jar. The gasket may have one more opening with a valve in it for clearing the smoke from the water jar not via the hose. In some cases the gasket may contain openings for more than one hose.
Water jar
Damascene woodworkers creating wood for hookahs, 19th century.Placed at the bottom of the hookah, the water jar is a container which the smoke from the tobacco passes through before it reaches the hose. By passing through water, the smoke gains moisture. This makes inhaling the smoke of the hookah easier than a cigarette's. Also the water jar allegedly functions as a filter for the smoke. The level of the water has to be higher than the lowest point of the body's tube in order for the smoke to pass through it. Liquids other than water may be added, such as a strong mixture of alcohol,spirit and/or fruit juice.
The plate
The plate is usually just below the bowl and is used for "dead" coals from previous smoking sessions. It is not vital for the operation of the hookah.
Grommets
Grommets in a hookah are usually placed between the bowl and the body, the body's gasket and the water jar and between the body and the hose. The reason for the usage of grommets although not essential (the usage of paper or tape has become common) will help to seal the joints between the parts, therefore decreasing the amount of air coming in and maximizing the smoke breathed in.
Operation
The jar at the bottom of the hookah is filled with water sufficient to submerge a few centimeters of the body tube, which is sealed tightly to it. Tobacco is placed inside the bowl at the top of the hookah and a burning charcoal is placed on top of the tobacco. Some cultures cover the bowl with perforated tin foil to separate the coal and the tobacco, which minimizes inhalation of coal ash with the smoke.
When one inhales via the hose, air is pulled through the coal and into the bowl. The air, hot from the charcoal, roasts, not burns, the tobacco, producing smoke. This smoke passes down through the body tube, which extends into the water in the jar. It bubbles up through the water and fills the top part of the jar, to which the hose is attached. When a smoker inhales from the hose, smoke passes into the lungs, and the change in pressure in the jar pulls more air through the charcoal, continuing the process.
The hookah's components must be sealed tightly with grommets, or air which does not flow through the coal will dilute the smoke.
Flavours
Molasses tobacco is sold in a variety of flavours. Some of the flavours in which it is available are derived from the addition of artificial flavourings; other manufacturers shun these. A few of the flavours are based upon the scent of flowers. Flavours include vanilla, coconut, rose, honey, strawberry, watermelon, mint, cherry, orange, apple, apricot, chocolate, coffee, grape, peach, cola, gum, bubblegum, vodka. fruitopia, etc. The Double-Apple (Persian:?????,Do-Sib) is also a very popular flavour in the middle-east by the every day hookah-smokers because of the strength. But most two-apple tobacco seen in the U.S. stores are just apple flavour and aren't as strong. Nakhla produces the most popular double apple in the industry.
For Health Benefits and Risks please read full article at the following
Source: http://en.wikipedia.org/wiki/Hookah
