A hookah is constructed from four fundamental components:
the base, vase, or smoke chamber, which is partially filled with water
the bowl or head, which contains the tobacco; the heating apparatus is placed on top
the pipe or stem which connects the bowl to the base by a tube that descends into the water
the hose, which connects to a second tube in the pipe that does not descend into the water, but only the air of the smoke chamber
These basic parts do not vary in function; naturally, there are any number of decorations or subtle variations in form. The heating apparatus is usually charcoal, but in Saudi Arabia and the Persian Gulf, electric heaters are common. The charcoal is usually placed on a metal mesh or perforated aluminium foil, but these are often omitted to produce a denser smoke. The hose may or may not be detachable — simple hookahs simply have a tube into the air of the smoke chamber; elaborate hookahs have three or more hoses in a single chamber, sometimes with filters attached at one or both ends of the hose. Traditionally, hookahs have been ornately decorated. Some modern hookahs bear little resemblance to older designs.
When a smoker inhales through the tube, a pressure difference forces air past the coal, heating the tobacco, which gives off smoke. The smoke is pulled down from the tobacco, and bubbles up through the water into the air of the smoke chamber. From there, it is drawn through the hose and inhaled by the smoker. Passing through the water partially filters tar and particulates from the tobacco smoke in addition to cooling it.
The design of a hookah allows for multiple hoses to lead to a single filtration chamber; this simplifies use by groups. Multiple hoses can, however, reduce suction and makes drawing smoke difficult or impossible. Some hookahs incorporate a ball-bearing check valve into each hose to combat this problem, while others require smokers to block the mouthpiece with their finger when not in use. Multi-hose hookahs are particularly popular in the Western world, where hookah smoking is a social phenomenon. They are not as common in Asia and Africa.
They are quite popular here in the States now. Although the people using them are often from the drug culture and they often use various drugs instead of tobacco.
Getting away from Hookahs:
Tobacco is dangerous no matter how a person uses it.